Definition

A negation suffix added at the end of a statement to humorously reverse or contradict what was just said; a comedic rhetorical device.

Example Usage

You're really smart. Not!

Origin

Popularized by the 1992 film Wayne's World as a comedic catchphrase; became widespread 90s slang.

Fun Fact

Had a brief but intense period of popularity in the early 1990s before falling out of common use.

Source: Definition backfill (hailey)