on the game

The story

From game (“fun, a fun activity, the fun of the chase, hunters' prey”), used in reference to sex since Old English and in particular reference to prostitution originally as lady or girl of the game in Early Modern English. In modern contexts, compare with the similar euphemistic use of sport.

First known use, by meaning

• 1739 Working as a thief.
• 1898 Working as a prostitute.