Which one should you use?
The default form tu es fou is informal and should be used with friends, family or peers. For a more colloquial or slang feel, you can use Tu es dingue.
Is there a formal and an informal way to say it?
In informal settings, such as with friends, family or peers, use tu es fou. For formal situations, you can use Vous êtes fou/folle to say "You are crazy" or more intense expressions like Vous avez perdu la raison ("You have lost your mind") or Vous délirez complètement ("You are completely deluded"). In very casual or slang contexts, you might use T'es cinglé(e) in a lighthearted way or T'as une case en moins to suggest someone lacks common sense.
How does it change in a sentence?
When speaking to a woman, use the feminine form tu es folle. If you are addressing a group of men or a mixed-gender group, use vous êtes fous. If you are addressing a group consisting only of women, use vous êtes folles.
Did you know?
- The word fou has a strange connection to the game of chess. It is thought to have been influenced by the Arabic word for 'elephant', which became the term for a bishop in chess. This traveled through Spanish and helped define the French sense of a 'court jester' or someone acting strangely.
- While fou means 'crazy', the French word for 'insane' or 'mad' can also be used to describe an intense passion, such as un amour fou for 'a wild love'.
- In French, describing someone as cinglé is a way to call them 'crazy' while implying they are slightly 'cracked' or 'broken', much like a piece of pottery.
Examples in context
- Tu es fou !You're crazy!This is useful for expressing the direct exclamation "You're crazy!"Tatoeba #829101 by Cocorico, translation #664251 by BlueLagoon
- Je ne crois pas que tu es fou.I don't think you're crazy.This is useful for expressing the thought "I don't think you're crazy.".Tatoeba #2990842 by nimfeo, translation #2276234 by CK
- Ne les laisse pas te dire que tu es fou.Don't let them tell you you're crazy.This is useful for expressing the command "Don't let them tell you you're crazy.".Tatoeba #4139882 by sacredceltic, translation #3730275 by CM
- Madame Dupont, vous êtes folle de penser cela.Madam Dupont, you are crazy to think that.
- Monsieur Martinez, vous êtes fou de faire ça.Mister Martinez, you are crazy to do that.
- Mademoiselle Lambert, vous délirez complètement en pensant cela.Miss Lambert, you are completely deluded to think that.
- Monsieur Dubois, vous délirez complètement avec votre théorie.Mr. Dubois, you are completely deluded with your theory.
- Tu es complètement tarée de faire ça !You are completely crazy to do that!
- Tu es taré de croire une chose pareille.You are crazy to believe such a thing.
- T'es cinglée de penser ça !You're crazy to think that!
- T'es complètement cinglé de vouloir faire ça.You're completely crazy to want to do that.
- T'as une case en moins pour dire ça.You're missing a compartment (in your head) to say that.
- Je crois que t'as une case en moins pour agir ainsi.I think you're missing a compartment (in your head) to act like that.
- 5 more sentences on Tatoeba
Example conversation
Hugo tells Léa a ridiculous idea he has.
- LéaTu veux vraiment sauter de ce haut ?Do you really want to jump from this height?
- HugoOui, c'est une aventure incroyable !Yes, it is an incredible adventure!
- LéaTu es fou, Hugo !You're crazy, Hugo!
- HugoMais non, je suis juste courageux.No, I am just brave.
Sources
- Word origins: Wiktionary entries fou, tu, CC BY-SA 4.0.
- Example sentences: Tatoeba CC BY 2.0 FR.
