Restrains wild beast (5)
I believe the answer is:
bates
'restrains' is the definition.
(bating is a kind of restraining)
'wild beast' is the wordplay.
'wild' indicates anagramming the letters.
'beast' anagrammed gives 'BATES'.
(Other definitions for bates that I've seen before include "short-story writer" , "motel owner" , "moderates" .)