What does “lâcher l’affaire” mean in French?

Lâcher l’affaire means to give up, to stop trying. Lâcher is “to let go of” and l’affaire is “the matter,” so you’re letting the whole thing drop. J’ai lâché l’affaire is “I gave up.” Said to someone else, lâche l’affaire ! means “drop it” or “let it go.” It’s casual and very common among younger speakers.

The neutral equivalent is laisser tomber (“let fall”), and abandonner is the formal one. In this sketch the comedian says his maths career ended at 2 × 2 = 4: j’ai lâché l’affaire. He follows it with c’est quoi ce délire ?, “what is this nonsense?”, and a rant about multiplying bananas you don’t have.