passer l’arme à gauche

To meet your end

A breezy, euphemistic way of saying someone has died, in the same spirit as kicking the bucket.

Le vieux chat du voisin a fini par passer l'arme à gauche après dix-huit belles années.

The neighbour's old cat finally passed on after eighteen good years.

Wiktionary calls the real origin unconfirmed, but lists the usual suspects: a beaten duellist ending up with his sword in his left hand, the old idea of the left standing for bad luck against a lucky right, or a nod to military funerals, where soldiers carried their rifles slung on the left arm. That last version, traced to the 19th century writer Pierre-Marie Quitard, tends to get repeated the most.