Pronunciation: (as'bak'wurdz), [key]
—adv. Slang (sometimes vulgar).
1. in an order or way reverse from the usual: You've sewn the sleeve on assbackwards.
2. in a manner incongruously or preposterously counter to what is customary, probable, or feasible: The plan fell apart because everything leading up to it was handled assbackwards. Also,ass'back'ward.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.