Rescue wild deer with bigger space (6)
I believe the answer is:
redeem
'rescue' is the definition.
(I've seen this before)
'wild deer with bigger space' is the wordplay.
'wild' is an anagram indicator.
'with' is a charade indicator (letters next to each other).
'bigger space' becomes 'em' (in printing, an em space is wider than an en space).
'deer' is an anagram of 'rede'.
'rede'+'em'='REDEEM'
(Other definitions for redeem that I've seen before include "Deliver from sin" , "Save, from hell or pawnbroker" , "Ransom" , "Regain possession in exchange for money" , "Make amends (for)" .)