Men in fashion, say (4)
I believe the answer is:
guys
'men' is the definition.
'fashion say' is the wordplay.
'fashion' becomes 'guise'.
'say' indicates a 'sounds like' (homophone) clue.
'guise' sounds like 'GUYS'.
'in' is the link.
(Other definitions for guys that I've seen before include "Men (with dolls?)" , "Bonfire Night effigies" , "Fellows" , "Makes fun of < hospital" , "Ridicules American men?" .)