Some slim men seem huge (7)
I believe the answer is:
immense
'huge' is the definition.
(I know that huge can be written as immense)
'some slim men seem' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the 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" .)