Not stale (5)
I believe the answer is:
fresh
'not stale' is the definition.
('fresh' is the opposite to 'stale')
This is the entire clue.
(Other definitions for fresh that I've seen before include "Informally impudent, not stale" , "New; strongish (breeze)" , "Cheeky (sl.)" , "Not canned or preserved" , "Saucy" .)