avoir un poil dans la main

to be very lazy

This expression describes someone who is lazy and doesn't like to work, especially with their hands.

Il a un poil dans la main, il ne fait jamais rien à la maison.

He's so lazy, he never does anything around the house.

First recorded in the Dictionnaire du bas-langage (1808) and spread through working-class circles in the 19th century. Workers mocked those who never used their hands. Hair can't grow on palms, so if yours has one, you clearly haven't been working.