Decide to leave, with "out" (3)
I believe the answer is:
opt
'decide to leave with out' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for opt that I've seen before include "Decide between possibilities, choose" , "Elect" , "Hold in the highest esteem" , "Have preference for something" , "Prefer, choose" .)