Derived from gank, gankers.
A Gank Monkey is a person who edits or makes a page on a site such as wikipedia or urban dictionary about how great they are. Some say that Gank Monkey was originally Wank Monkey, because Gank Monkeys are usually such losers that they never get beyond masturbation in terms of sexual contact, which is why they spend so much time talking about themselves of the internet.
1: Killstyk: He is so cool, I wish I was him. The killstyk is the best WOW player ever, he kills so many noobs, that maybe his rank in the server will go up from 3 to one. Heh heh. -Edited by Killstyk.
The above is a Gank Monkey.
A behavioral trait found in sales people. Where by one sales person tends to steal another sales persons lead. This act similar to a monkey stealing another monkeys banana and looking around like it's no big thing, while all the while knowing it's wrong.
You are such a gank monkey, you knew that customer was mine and you went ahead and sold him a system behind my back.
YOU Gank Monkey, that's my sales lead.