Elle a vendu la mèche.
ell lah vah-DEW lah MESH. Click below to hear this pronounced!
She let the cat out of the bag.
You do know that cat is chat and bag is sac, right? And you did notice that they aren’t in the French sentence?
Ah, you are so observant. Yes, we have yet another case of Sneaky Sayings.
Elle a vendu means she sold. La mèche means a lock of hair. Or it can mean a candle wick. Or a bomb fuse. Take your pick! And Elle est de mèche avec lui means She is in league with him. I’m not even going to try to guess whether they set bombs together, run a candle shop, or got their hair entangled while stealing a kiss. None of my business.
All we know for sure is that it wasn’t a good idea and she could get in trouble for it. Especially if what she revealed was the plans for somebody’s surprise party!