Garment that's right with a gong? (4)
I believe the answer is:
robe
'garment' is the definition.
(I've seen this before)
'right with a gong?' is the wordplay.
'right' becomes 'r' (common abbreviation).
'with' is a charade indicator (letters next to each other).
'a gong?' becomes 'obe' (I've seen this before).
'r'+'obe'='ROBE'
'that's' acts as a link.
(Other definitions for robe that I've seen before include "official dress" , "Clerical garment" , "Any loose flowing garment" , "Formal vestment" , "Ceremonial garb" .)