Write a clever dictionary definition!

Let’s play Ambrose Bierce style here. I, as is customary for the OP to do, will start.

Prostitute - A coin-operated sex machine.

Wisdom Teeth - Teeth that grow in the back of the mouth during late adolescensce. So called because they are traditionally given to a dentist in exchange for consciousness-expanding substances such as nitrous oxide and codeine.

LC