If you're looking for a word in French that describes someone who is not very intelligent, there are more neutral ways to say it:
* Naïf: This word means "naive" and can be used to describe someone who is innocent or lacking in experience.
* Bête: This word means "stupid" but is considered more informal and can be offensive if used in a harsh way.
* Imbécile: This word means "imbecile" and is a stronger term than "bête."
Remember, it's important to choose your words carefully and avoid using language that is hurtful or disrespectful.