Fashionable matches for prisoners (7)
I believe the answer is:
inmates
'for prisoners' is the definition.
(inmate is a kind of prisoner)
'fashionable matches' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'matches' becomes 'mates' ('mate' can be a synonym of 'match').
'in'+'mates'='INMATES'
(Other definitions for inmates that I've seen before include "Prisoners" , "Ties man (anag.)" , "Inhabitants" .)