backflip

Short definition from Wiktionary

Noun

1. 1
   An act of rotating one's body 360 degrees in the backward direction.
2. 2
   A total reversal in policy or opinion; a volte-face, a U-turn.

Verb

1. 1
   To perform a backflip (rotation of body).
2. 2
   To completely reverse a policy or opinion; perform a U-turn.