Formal/Neutral:
* Fou/Folle: This is the most basic and common word for "crazy" in French. It can be used for both men and women.
* Détraqué/Détraquée: This word translates more closely to "unhinged" or "mentally unstable."
* Délirant/Délirante: This means "delusional" or "having delusions."
Informal/Slang:
* Dingue: This is a very common slang term for "crazy" and can be used in both positive and negative contexts.
* Barjot: This is a more informal and slightly derogatory word for "crazy."
* Foufou: This is a slang term that means "crazy" but is often used in a playful or affectionate way.
* Taré/Tarée: This is a harsh and often offensive word that means "crazy" or "insane."
Figurative/Idiom:
* Avoir la tête à l'envers: This literally translates to "have one's head upside down" and means to be "crazy" or "out of one's mind."
* Être à côté de ses pompes: This literally means "to be beside one's pumps" and is a way of saying someone is "crazy" or "acting strange."
Example Sentences:
* Il est complètement fou! (He's completely crazy!)
* Elle est détraquée depuis qu'elle a perdu son travail. (She's been unhinged since she lost her job.)
* Tu es dingue de faire ça! (You're crazy for doing that!)
* Ce type est vraiment barjot. (That guy is really crazy.)
The best choice for you will depend on the situation and the specific meaning you want to convey. Remember that slang terms can be considered offensive depending on the context.