1.) One who cannot keep his word and always backs out without notice.

2.) No Call, No Show!
Tony: You going to come over tomorrow for the game?
Bill: Yea I'll definatly be there!
@the party.
Justin:Where is bill at?
Tony: I don't know he never called.
Justin: Good ol' Back out Bill
by Tony89 August 9, 2007
Get the back out bill mug.