Donner sa langue au chat, literally “to give one’s tongue to the cat”, means to give up or stop guessing. Fun fact, the original expression was Jeter sa langue aux chiens (“To throw one’s tongue to the dogs”). Well, if you couldn’t guess any more, your tongue was useless, so you could throw it away like leftover food for the dogs. It is however unclear how Jeter sa langue aux chiens switched to Donner sa langue au chat in the 19th century.
French with Valerie 