I. Person or persons in a group who provide minimal roles in combat but have an abundance of talents and abilities, which keep them useful to the party.
II. Member of a group who prides him or herself on their proficiency with non-combat related abilities.
III. Character with too many skills, creating an imbalance in gameplay.
Origin: From Dungeons and Dragons, originally referring to the Thief (or Rogue, in later editions). The class features a prolific number of skill points both at character creation and throughout the later levels. The phrase comes from the Rogue’s archetype as the nimble cat burglar and the Halfling, whose stature makes them physically similar to monkeys.
Synonyms: Skill Whore
"She can't do damage for crap, but we keep her around because she's such a skill monkey. I mean, who else is going to pick all the locks?"