Member wearing man's clothes (8)
I believe the answer is:
garments
'clothes' is the definition.
(I know this)
'member wearing man's' is the wordplay.
'member' becomes 'arm' (member can mean a limb).
'wearing' indicates putting letters inside.
'man's' becomes 'gents' (gent is a kind of man).
'arm' going into 'gents' is 'GARMENTS'.
(Other definitions for garments that I've seen before include "Articles of clothing" , "clothes" .)