être malin comme un singe

To be very clever

This expression describes someone who is ingenious, shrewd, and clever, using their intelligence to outplay others. It evokes the cleverness and ingenuity that monkeys are known to display.

Ce petit garçon est malin comme un singe, il trouve toujours une solution à ses problèmes.

This little boy is clever as a monkey, he always finds a solution to his problems.

In the Middle Ages, monkeys were thought to be related to the devil. The association with trickery stuck, though these days it's more affectionate than sinister.