One with raincoat returned, only for undergarment (8)
I believe the answer is:
camisole
'undergarment' is the definition.
(camisole is a kind of undergarment)
'one with raincoat returned only' is the wordplay.
'one' becomes 'i' (Roman numeral).
'with' is a charade indicator (letters next to each other).
'raincoat' becomes 'mac' (mac is a kind of raincoat).
'returned' says the letters should be written in reverse.
'only' becomes 'sole' ('sole' can be a synonym of 'only').
'mac' backwards is 'cam'.
'i' after 'cam' is 'cami'.
'cami'+'sole'='CAMISOLE'
'for' is the link.
(Other definitions for camisole that I've seen before include "Item of lingerie" , "Underbodice with shoulder straps" , "Loose undergarment" , "jacket" , "Close aim (anag.)" .)