Blaze held back by sheriff (4)
I believe the answer is:
fire
'blaze' is the definition.
(I know that blaze can be written as fire)
'held back by sheriff' is the wordplay.
'back by' says the letters should be written backwards.
'held' says the answer is hidden in the clue.
'erif' is hidden within 'sheriff'.
'erif' backwards is 'FIRE'.
(Other definitions for fire that I've seen before include "See 5" , "Weaponry" , "Flame - dismiss - shoot" , "Blaze - sack" , "Trigger" .)