diff --git a/package-lock.json b/package-lock.json
index 84a4c3a2..330c0ecf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,6 +10,7 @@
       "dependencies": {
         "@tailwindcss/vite": "^4.2.2",
         "canvas-confetti": "^1.9.4",
+        "leo-profanity": "^1.9.0",
         "lucide-vue-next": "^1.0.0",
         "pinia": "^3.0.4",
         "tailwindcss": "^4.2.2",
@@ -3509,6 +3510,13 @@
         "url": "https://github.com/sponsors/isaacs"
       }
     },
+    "node_modules/french-badwords-list": {
+      "version": "1.0.7",
+      "resolved": "https://registry.npmjs.org/french-badwords-list/-/french-badwords-list-1.0.7.tgz",
+      "integrity": "sha512-H1ziKs2PJh2+UXZ9oCGJ/rRQpsI9NBykGf2Sc7WaKaj1OnWFuBXfsvANTdRcfVmOghGQaUmRyZ1hJOPbDpy04Q==",
+      "license": "MIT",
+      "optional": true
+    },
     "node_modules/fsevents": {
       "version": "2.3.2",
       "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
@@ -3919,6 +3927,19 @@
         "json-buffer": "3.0.1"
       }
     },
+    "node_modules/leo-profanity": {
+      "version": "1.9.0",
+      "resolved": "https://registry.npmjs.org/leo-profanity/-/leo-profanity-1.9.0.tgz",
+      "integrity": "sha512-vMrrrjsbT+fA5I/1rlBEVT5YjJsw1ASIVF8/xBEdZ6ylsg5AEIBrEvHxwe5XAmfVuTBi7aw2KcO2L3s9ddpKzw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=18"
+      },
+      "optionalDependencies": {
+        "french-badwords-list": "^1.0.7",
+        "russian-bad-words": "^0.5.0"
+      }
+    },
     "node_modules/levn": {
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/levn/-/levn-0.4.1.tgz",
@@ -5033,6 +5054,16 @@
         "queue-microtask": "^1.2.2"
       }
     },
+    "node_modules/russian-bad-words": {
+      "version": "0.5.0",
+      "resolved": "https://registry.npmjs.org/russian-bad-words/-/russian-bad-words-0.5.0.tgz",
+      "integrity": "sha512-euNvEYki6iYYpkNbeudW+lEMMYGEmN7EBwVF8ezlbv0bZoQpVYB7W10cCeUIGV7Ed50sJynLQ0c559q5iI0ejQ==",
+      "license": "MIT",
+      "optional": true,
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/sax": {
       "version": "1.6.0",
       "resolved": "https://registry.npmjs.org/sax/-/sax-1.6.0.tgz",
diff --git a/package.json b/package.json
index 4debe6d3..78f5d70f 100644
--- a/package.json
+++ b/package.json
@@ -22,6 +22,7 @@
   },
   "dependencies": {
     "@tailwindcss/vite": "^4.2.2",
+    "leo-profanity": "^1.9.0",
     "canvas-confetti": "^1.9.4",
     "lucide-vue-next": "^1.0.0",
     "pinia": "^3.0.4",
diff --git a/src/mystery/components/MysterySubmissionForm.vue b/src/mystery/components/MysterySubmissionForm.vue
index 98c4d770..af57b84d 100644
--- a/src/mystery/components/MysterySubmissionForm.vue
+++ b/src/mystery/components/MysterySubmissionForm.vue
@@ -1,89 +1,108 @@
 <script setup lang="ts">
-import { computed, ref } from 'vue'
-import { useI18n } from 'vue-i18n'
-import { moderateText } from '@/shared/moderation/banned-words'
+import { computed, ref } from "vue";
+import { useI18n } from "vue-i18n";
+import { moderateText } from "@/shared/moderation/banned-words";
+import { useProfanityFilter } from "@/shared/composables/useProfanityFilter.ts";
 
-const { t } = useI18n()
+const { t } = useI18n();
+const { hasProfanity } = useProfanityFilter();
 
 const props = defineProps<{
-  submitting: boolean
-  successMessage?: string | null
-  errorMessage?: string | null
-  bannedWords?: string[]
-}>()
+  submitting: boolean;
+  successMessage?: string | null;
+  errorMessage?: string | null;
+  bannedWords?: string[];
+}>();
 
 const emit = defineEmits<{
-  submit: [description: string, file: File | null]
-}>()
-
-const ALLOWED_TYPES = ['image/jpeg', 'image/png', 'image/gif', 'image/webp']
-
-const description = ref('')
-const attachmentFile = ref<File | null>(null)
-const attachmentPreviewUrl = ref<string | null>(null)
-const uploadError = ref<string | null>(null)
-const moderation = computed(() =>
-  moderateText([description.value], props.bannedWords ?? []),
-)
-const moderationError = computed(() =>
-  moderation.value.hasBlockedWords
-    ? t('mystery.submitForm.bannedWords', {
-        words: moderation.value.blockedWords.join(', '),
-      })
-    : null,
-)
+  submit: [description: string, file: File | null];
+}>();
+
+const ALLOWED_TYPES = ["image/jpeg", "image/png", "image/gif", "image/webp"];
+
+const description = ref("");
+const attachmentFile = ref<File | null>(null);
+const attachmentPreviewUrl = ref<string | null>(null);
+const uploadError = ref<string | null>(null);
+
+const moderation = computed(() => {
+  const text = description.value;
+
+  const bannedCheck = moderateText([text], props.bannedWords ?? []);
+  const profanityDetected = hasProfanity(text);
+
+  return {
+    ...bannedCheck,
+    hasProfanity: profanityDetected,
+    hasAnyViolation: bannedCheck.hasBlockedWords || profanityDetected,
+  };
+});
+
+const moderationError = computed(() => {
+  if (moderation.value.hasBlockedWords) {
+    return t("mystery.submitForm.bannedWords", {
+      words: moderation.value.blockedWords.join(", "),
+    });
+  }
+
+  if (moderation.value.hasProfanity) {
+    return t("mystery.submitForm.profanity");
+  }
+
+  return null;
+});
 
 const canSubmit = () =>
   description.value.trim().length > 0 &&
   !uploadError.value &&
-  !moderation.value.hasBlockedWords
+  !moderation.value.hasAnyViolation;
 
 function onFileSelected(event: Event) {
-  const input = event.target as HTMLInputElement
-  const file = input.files?.[0] ?? null
+  const input = event.target as HTMLInputElement;
+  const file = input.files?.[0] ?? null;
 
-  uploadError.value = null
+  uploadError.value = null;
 
   if (attachmentPreviewUrl.value) {
-    URL.revokeObjectURL(attachmentPreviewUrl.value)
-    attachmentPreviewUrl.value = null
+    URL.revokeObjectURL(attachmentPreviewUrl.value);
+    attachmentPreviewUrl.value = null;
   }
 
   if (file && !ALLOWED_TYPES.includes(file.type)) {
-    uploadError.value = t('mystery.submitForm.unsupportedFileType')
-    input.value = ''
-    return
+    uploadError.value = t("mystery.submitForm.unsupportedFileType");
+    input.value = "";
+    return;
   }
 
-  attachmentFile.value = file
-  if (file) attachmentPreviewUrl.value = URL.createObjectURL(file)
+  attachmentFile.value = file;
+  if (file) attachmentPreviewUrl.value = URL.createObjectURL(file);
 }
 
 function clearAttachment() {
   if (attachmentPreviewUrl.value)
-    URL.revokeObjectURL(attachmentPreviewUrl.value)
-  attachmentFile.value = null
-  attachmentPreviewUrl.value = null
-  uploadError.value = null
+    URL.revokeObjectURL(attachmentPreviewUrl.value);
+  attachmentFile.value = null;
+  attachmentPreviewUrl.value = null;
+  uploadError.value = null;
 }
 
 function handleSubmit() {
-  if (!canSubmit()) return
-  emit('submit', description.value.trim(), attachmentFile.value)
+  if (!canSubmit()) return;
+  emit("submit", description.value.trim(), attachmentFile.value);
 }
 
-defineExpose({ reset })
+defineExpose({ reset });
 
 function reset() {
-  description.value = ''
-  clearAttachment()
+  description.value = "";
+  clearAttachment();
 }
 </script>
 
 <template>
   <div class="mx-auto max-w-xl rounded-2xl bg-white p-6 shadow-md">
     <h2 class="mb-4 text-lg font-semibold text-gray-900">
-      {{ t('mystery.submitForm.heading') }}
+      {{ t("mystery.submitForm.heading") }}
     </h2>
 
     <div
@@ -100,7 +119,7 @@ function reset() {
           for="mystery-description"
           class="mb-1 block text-sm font-semibold text-gray-700"
         >
-          {{ t('mystery.submitForm.descriptionLabel') }}
+          {{ t("mystery.submitForm.descriptionLabel") }}
         </label>
         <textarea
           id="mystery-description"
@@ -127,7 +146,7 @@ function reset() {
             class="w-full rounded-lg border border-red-300 bg-white py-1 text-xs font-semibold text-red-600 hover:bg-red-50"
             @click="clearAttachment"
           >
-            {{ t('mystery.submitForm.removeImage') }}
+            {{ t("mystery.submitForm.removeImage") }}
           </button>
         </div>
 
@@ -138,7 +157,7 @@ function reset() {
         >
           <span class="text-2xl text-amber-500">&#128247;</span>
           <span class="text-center text-xs font-semibold text-gray-400">
-            {{ t('mystery.submitForm.uploadLabel') }}
+            {{ t("mystery.submitForm.uploadLabel") }}
           </span>
           <input
             id="mystery-file"
@@ -166,8 +185,8 @@ function reset() {
       :disabled="!canSubmit() || submitting"
       @click="handleSubmit"
     >
-      <span v-if="submitting">{{ t('mystery.submitForm.submitting') }}</span>
-      <span v-else>{{ t('mystery.submitForm.submit') }}</span>
+      <span v-if="submitting">{{ t("mystery.submitForm.submitting") }}</span>
+      <span v-else>{{ t("mystery.submitForm.submit") }}</span>
     </button>
   </div>
 </template>
diff --git a/src/notifications/notifications.types.ts b/src/notifications/notifications.types.ts
index c5aa89b0..c3393d05 100644
--- a/src/notifications/notifications.types.ts
+++ b/src/notifications/notifications.types.ts
@@ -3,6 +3,7 @@ export const notificationTypes = [
   'GAME_COMPLETED',
   'PUPIL_STUCK',
   'WEEKLY_MYSTERY_SUBMITTED',
+  'INAPPROPRIATE_BEHAVIOUR',
 ] as const
 
 export type NotificationType = (typeof notificationTypes)[number]
diff --git a/src/profile/pages/PupilProfilePage.vue b/src/profile/pages/PupilProfilePage.vue
index 92254ecd..f2dfc5ef 100644
--- a/src/profile/pages/PupilProfilePage.vue
+++ b/src/profile/pages/PupilProfilePage.vue
@@ -1,30 +1,72 @@
 <script setup lang="ts">
-import { computed, onMounted, ref, watch } from 'vue'
-import { useI18n } from 'vue-i18n'
-import { RouterLink } from 'vue-router'
-import { useAuthStore } from '@/auth/model/auth.store'
-import AvatarComponent from '@/avatar/components/AvatarComponent.vue'
+import { computed, onMounted, ref, watch } from "vue";
+import { useI18n } from "vue-i18n";
+import { RouterLink, useRouter } from "vue-router";
+import { useAuthStore } from "@/auth/model/auth.store";
+import AvatarComponent from "@/avatar/components/AvatarComponent.vue";
+import { requestUpdateCurrentUserProfile } from "@/profile/api/profile.api";
+import { requestClassroomBannedWords } from "@/shared/moderation/moderation.api.ts";
+import { useProfanityFilter } from "@/shared/composables/useProfanityFilter.ts";
 import avatarBackground from '@/assets/avatar/background/avatar-background.png'
-import { requestUpdateCurrentUserProfile } from '@/profile/api/profile.api'
 
 const { t } = useI18n()
 const authStore = useAuthStore()
 
-const defaultDisplayName = computed(() => t('pupilHome.defaultName'))
-const pupilProfile = computed(() => authStore.user?.pupilProfile ?? null)
-const currentLevel = computed(() => pupilProfile.value?.currentLevel ?? 1)
-const totalXp = computed(() => pupilProfile.value?.totalXp ?? 0)
-const savedDisplayName = ref(defaultDisplayName.value)
-const draftDisplayName = ref(defaultDisplayName.value)
-const isEditingName = ref(false)
-const isSavingName = ref(false)
-const saveErrorMessage = ref<string | null>(null)
-const saveSuccessMessage = ref<string | null>(null)
-const trimmedDraftDisplayName = computed(() => draftDisplayName.value.trim())
+const defaultDisplayName = computed(() => t("pupilHome.defaultName"));
+const pupilProfile = computed(() => authStore.user?.pupilProfile ?? null);
+const currentLevel = computed(() => pupilProfile.value?.currentLevel ?? 1);
+const totalXp = computed(() => pupilProfile.value?.totalXp ?? 0);
+const savedDisplayName = ref(defaultDisplayName.value);
+const draftDisplayName = ref(defaultDisplayName.value);
+const isEditingName = ref(false);
+const isSavingName = ref(false);
+const saveErrorMessage = ref<string | null>(null);
+const saveSuccessMessage = ref<string | null>(null);
+const trimmedDraftDisplayName = computed(() => draftDisplayName.value.trim());
 const normalizedDraftDisplayName = computed(() =>
   trimmedDraftDisplayName.value.length > 0
     ? trimmedDraftDisplayName.value
     : defaultDisplayName.value,
+);
+const isNameDirty = computed(
+  () => normalizedDraftDisplayName.value !== savedDisplayName.value,
+);
+const { hasProfanity } = useProfanityFilter();
+const bannedWords = ref<string[]>([]);
+
+async function loadBannedWords() {
+  if (
+    !authStore.authorizationHeader ||
+    !pupilProfile.value?.currentClassroomId
+  ) {
+    bannedWords.value = [];
+    return;
+  }
+
+  try {
+    const result = await requestClassroomBannedWords(
+      pupilProfile.value.currentClassroomId,
+      authStore.authorizationHeader,
+    );
+    bannedWords.value = result.map((entry) => entry.word.toLowerCase());
+  } catch {
+    bannedWords.value = [];
+  }
+}
+
+function containsBannedWord(text: string, words: string[]) {
+  const normalized = text.toLowerCase();
+  return words.some((word) => normalized.includes(word));
+}
+
+const hasBadWords = computed(() => {
+  const name = normalizedDraftDisplayName.value;
+
+  return hasProfanity(name) || containsBannedWord(name, bannedWords.value);
+});
+  trimmedDraftDisplayName.value.length > 0
+    ? trimmedDraftDisplayName.value
+    : defaultDisplayName.value,
 )
 const isNameDirty = computed(
   () => normalizedDraftDisplayName.value !== savedDisplayName.value,
@@ -39,11 +81,13 @@ const avatarPreviewStyle = computed(() => ({
 watch(
   pupilProfile,
   (profile) => {
-    const displayName = profile?.displayName?.trim() || defaultDisplayName.value
-    savedDisplayName.value = displayName
+    const displayName =
+      profile?.displayName?.trim() || defaultDisplayName.value;
+    savedDisplayName.value = displayName;
     if (!isEditingName.value) {
-      draftDisplayName.value = displayName
+      draftDisplayName.value = displayName;
     }
+    void loadBannedWords();
   },
   { immediate: true },
 )
@@ -54,23 +98,23 @@ const profileStats = computed(() => [
     value: String(currentLevel.value),
   },
   {
-    label: t('pupilProfile.xpLabel'),
+    label: t("pupilProfile.xpLabel"),
     value: String(totalXp.value),
   },
-])
+]);
 
 function startEditingName() {
-  draftDisplayName.value = savedDisplayName.value
-  saveErrorMessage.value = null
-  saveSuccessMessage.value = null
-  isEditingName.value = true
+  draftDisplayName.value = savedDisplayName.value;
+  saveErrorMessage.value = null;
+  saveSuccessMessage.value = null;
+  isEditingName.value = true;
 }
 
 function cancelEditingName() {
-  draftDisplayName.value = savedDisplayName.value
-  saveErrorMessage.value = null
-  saveSuccessMessage.value = null
-  isEditingName.value = false
+  draftDisplayName.value = savedDisplayName.value;
+  saveErrorMessage.value = null;
+  saveSuccessMessage.value = null;
+  isEditingName.value = false;
 }
 
 async function saveDisplayName() {
@@ -82,22 +126,28 @@ async function saveDisplayName() {
     return
   }
 
-  isSavingName.value = true
-  saveErrorMessage.value = null
-  saveSuccessMessage.value = null
+  isSavingName.value = true;
+  saveErrorMessage.value = null;
+  saveSuccessMessage.value = null;
 
   try {
-    const updatedDisplayName = normalizedDraftDisplayName.value
+    const updatedDisplayName = normalizedDraftDisplayName.value;
+
+    if (hasProfanity(updatedDisplayName)) {
+      saveErrorMessage.value = t("pupilProfile.nameProfanityError");
+      isSavingName.value = false;
+      return;
+    }
 
     await requestUpdateCurrentUserProfile(authStore.authorizationHeader, {
       displayName: normalizedDraftDisplayName.value,
-    })
+    });
 
-    authStore.updatePupilDisplayName(updatedDisplayName)
-    savedDisplayName.value = updatedDisplayName
-    draftDisplayName.value = savedDisplayName.value
-    saveSuccessMessage.value = t('pupilProfile.nameUpdateSuccess')
-    isEditingName.value = false
+    authStore.updatePupilDisplayName(updatedDisplayName);
+    savedDisplayName.value = updatedDisplayName;
+    draftDisplayName.value = savedDisplayName.value;
+    saveSuccessMessage.value = t("pupilProfile.nameUpdateSuccess");
+    isEditingName.value = false;
 
     try {
       await authStore.fetchCurrentUserProfile()
@@ -192,7 +242,7 @@ onMounted(() => {
             <div class="flex flex-wrap gap-3">
               <button
                 class="inline-flex items-center justify-center rounded-lg border border-zinc-900 bg-zinc-900 px-4 py-3 text-white transition hover:bg-zinc-800 focus:outline-none focus:ring-2 focus:ring-zinc-900/20"
-                :disabled="!isNameDirty || isSavingName"
+                :disabled="!isNameDirty || isSavingName || hasBadWords"
                 type="submit"
               >
                 {{
@@ -212,6 +262,9 @@ onMounted(() => {
             </div>
           </form>
 
+          <p v-if="hasBadWords" class="text-sm text-red-600">
+            {{ t("pupilProfile.nameProfanityError") }}
+          </p>
           <p v-if="saveSuccessMessage" class="mt-4 text-sm text-emerald-700">
             {{ saveSuccessMessage }}
           </p>
diff --git a/src/shared/composables/useProfanityFilter.ts b/src/shared/composables/useProfanityFilter.ts
new file mode 100644
index 00000000..18578b71
--- /dev/null
+++ b/src/shared/composables/useProfanityFilter.ts
@@ -0,0 +1,58 @@
+import leoProfanity from 'leo-profanity'
+
+let initialized = false
+
+function init() {
+  if (initialized) return
+
+  leoProfanity.clearList()
+
+  leoProfanity.loadDictionary('en')
+
+  leoProfanity.add(['faen', 'jævlig', 'dritt', 'helvete', 'idiot'])
+
+  initialized = true
+}
+
+// normalization
+function normalize(text: string) {
+  return text
+    .toLowerCase()
+    .replace(/[@4]/g, 'a')
+    .replace(/1/g, 'i')
+    .replace(/3/g, 'e')
+    .replace(/0/g, 'o')
+    .replace(/\s+/g, '')
+    .replace(/[^a-zæøå]/g, '')
+}
+
+export function useProfanityFilter() {
+  init()
+
+  function hasProfanity(text: string): boolean {
+    const normalized = normalize(text)
+
+    if (leoProfanity.check(text) || leoProfanity.check(normalized)) {
+      return true
+    }
+
+    const badWords = leoProfanity.list()
+
+    return badWords.some((word) => normalized.includes(word))
+  }
+
+  function clean(text: string): string {
+    return leoProfanity.clean(text)
+  }
+
+  function sanitize(text: string): string {
+    if (!hasProfanity(text)) return text
+    return clean(text)
+  }
+
+  return {
+    hasProfanity,
+    clean,
+    sanitize,
+  }
+}