Some slim men seem huge (7)
I believe the answer is:
immense
'huge' is the definition.
(synonyms)
'some slim men seem' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'IMMENSE' is hidden in the letters of 'slim men seem'.
(Other definitions for immense that I've seen before include "Unusually great in size" , "Massive" , "Very big, really huge" , "Unctuously ingratiating" , "Extremely large or great" .)