Literally: the cow
Meaning: A bit like the American expression “holy cow!” La vache (‘la vahsh’) can literally be translated as ‘the cow’, but is actually used as an expression of surprise, admiration, or disappointment, similar to ‘damn!’ or ‘OMG!’.
La vache can be positive, negative, or neutral, depending on the context.
Origins: 17th century, when farmers would bring a cow into town with them to demonstrate to the villagers that the milk, they were selling was fresh.
La vache, tu arrives tôt ! Holy cow, you're early!
La vache ! Qu'est-ce que tu as fait ? Damnit, what have you done!?
La vache, j'ai trouvé 100 euros ! Wow, I found 100 euros!