To draw from behind the back [+accusative = a knife etc.] (as also bare back).
To withdraw from something one has agreed to do.
To exit a mode or function.
To undo (a change).
Coordinate terms: cancel, call off, get cold feet
To reverse (a vehicle) from a confined space.
See also: sell short
To dare (someone) to not withdraw from a challenge.
To bet on someone losing.
Coordinate term: scare off
Used other than figuratively or idiomatically: see turn, coat.
To turn against a previous affiliation or allegiance.