Pune

A pune or a play on words is often spoken by Discworld characters when they tell a not very funny joke based on word play.

One particular pune that appears a lot on the Discworld is A leopard can't change his shorts.

Named after the founder of the Fools Guild one Jean-Paul Pune who, in his magnum opus, Essay on a form of wit devotes 160,000 words to defining the Five Great Classes and seventy-three sub-classes of the Pune or play on words, which all students at the Fools' Guild are expected to commit to memory on pain of pain.

Annotation

The very name Pune is a pun, or play on words, on the Roundworld word pun.