Opposite or contrary to what is expected, completely disordered or disarranged, or that which is done incompetently. A playful, euphemistic rearranging of "ass-backwards." That's the last time I let you fix the electrical work by yourself. You've wired it all bass-ackward! I must not be completely awake yet, I just put my pants on bass-ackward!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.