back out

Short definition from Wiktionary

Verb

1. 1
   To reverse (a vehicle) from a confined space.
2. 2
   To withdraw from something one has agreed to do.
3. 3
   To convince (someone) to withdraw from a challenge.
4. 4
   To bet on someone losing.
5. 5
   To undo (a change).
6. 6
   To exit a mode or function.
7. 7
   To draw from behind the back (a knife etc.) (as also bare back).