adverbslang, humorous, euphemistic US
Backwards, back to front, the wrong way round; in a manner contrary to what is usual, expected, or logical.
adjectiveslang, humorous, euphemistic US
Contrary to what is usual, expected, or logical; back-to-front, muddled, perverse.
1960s. Euphemistic or humorous alteration (with transposition of elements) of ass-backward.