diff --git a/api/src/nlp/controllers/nlp-entity.controller.spec.ts b/api/src/nlp/controllers/nlp-entity.controller.spec.ts
index 6e82b9cd..2f57c62f 100644
--- a/api/src/nlp/controllers/nlp-entity.controller.spec.ts
+++ b/api/src/nlp/controllers/nlp-entity.controller.spec.ts
@@ -9,6 +9,7 @@
 import { CACHE_MANAGER } from '@nestjs/cache-manager';
 import {
   BadRequestException,
+  ConflictException,
   MethodNotAllowedException,
   NotFoundException,
 } from '@nestjs/common';
@@ -289,6 +290,17 @@ describe('NlpEntityController', () => {
       expect(result.weight).toBe(updatedNlpEntity.weight);
     });
 
+    it('should throw an exception if entity is builtin but weight not provided', async () => {
+      await expect(
+        nlpEntityController.updateOne(buitInEntityId!, {
+          name: 'updated',
+          doc: '',
+          lookups: ['trait'],
+          builtin: false,
+        } as any),
+      ).rejects.toThrow(ConflictException);
+    });
+
     it('should update only the weight of the builtin entity', async () => {
       const updatedNlpEntity: NlpEntityUpdateDto = {
         weight: 8,
diff --git a/api/src/nlp/controllers/nlp-entity.controller.ts b/api/src/nlp/controllers/nlp-entity.controller.ts
index 32d22b11..1deb0c83 100644
--- a/api/src/nlp/controllers/nlp-entity.controller.ts
+++ b/api/src/nlp/controllers/nlp-entity.controller.ts
@@ -9,6 +9,7 @@
 import {
   BadRequestException,
   Body,
+  ConflictException,
   Controller,
   Delete,
   Get,
@@ -158,9 +159,18 @@ export class NlpEntityController extends BaseController<
       throw new NotFoundException(`NLP Entity with ID ${id} not found`);
     }
 
-    if (nlpEntity.builtin && nlpEntityDto.weight) {
-      // Only allow weight update for builtin entities
-      return await this.nlpEntityService.updateWeight(id, nlpEntityDto.weight);
+    if (nlpEntity.builtin) {
+      if (nlpEntityDto.weight) {
+        // Only allow weight update for builtin entities
+        return await this.nlpEntityService.updateWeight(
+          id,
+          nlpEntityDto.weight,
+        );
+      } else {
+        throw new ConflictException(
+          `Cannot update builtin NLP Entity ${nlpEntity.name} except for weight`,
+        );
+      }
     }
 
     return await this.nlpEntityService.updateOne(id, nlpEntityDto);