Some populist unfortunately from Knock (4)
I believe the answer is:
stun
'knock' is the definition.
(thesaurus)
'some populist unfortunately from' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'STUN' is hidden within 'populist unfortunately from'.
(Other definitions for stun that I've seen before include "what a cracker may do?" , "Render temporarily senseless" , "deliver a knock-out blow" , "Surprise greatly or daze" , "Dumbfound" .)