ass-backwards

Short definition from Wiktionary

Adjective

1. 1
   Oriented backwards, particularly after a mishap.
2. 2
   Hopelessly misguided; contrary to what is normal, expected, or logical; having taken the utterly wrong choice.
3. 3
   Alternative spelling of ass-backwards.

Adverb

1. 1
   Moving backwards, that is, rear end first.
2. 2
   In a hopelessly misguided manner; in a manner contrary to what is normal, expected, or logical.