A very oftenly used insult used by the immature population. Other more adult versions of this are examples such as Jack Ass, or plainly Ass. "Jack" is heard to be a old famous donkey from medevial times, and a munchie is that pesky little green man that is used in the old game by Macintosh called Super Munchers
Get awy from me Jack Munchie.
by D3guy2006 June 21, 2005