Munchkin

Munchkin is a derogatory term for a style of play more commonly known as power-gaming. The munchkins were the dwarf-like characters in the movie The Wizard of Oz (which was widely shown on television and is well-known in American pop culture). Presumably the connection is that the munchkins' short stature and falsetto voices made them appear puerile.

The term was common on the Berk List in the 1990s. More recently, the Ars Magica Fan Community has become more polite and accepting, and discourages insulting other players for how they choose to play the game. Power-gamer is the preferred term.