slang A crazy, insane, or very eccentric person. Can be hyphenated and used as a modifier before a noun. Some wack job on the street came over to us, spouting about the end of the world. Most of my family thinks I'm a wack job just because I live life my own way. How that wack-job senator got reelected is beyond me!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.