Stupefy some most unlikely people (4)
I believe the answer is:
stun
'stupefy' is the definition.
(I know that stupefy can be written as stun)
'some most unlikely people' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'STUN' is hidden within 'most unlikely people'.
(Other definitions for stun that I've seen before include "Nuts (anag)" , "Dumbfound" , "Render insensitive" , "Put out for the count" , "'Shock, daze (4)'" .)