Tasteless stuff edging plain upholstery fabric (7)
I believe the answer is:
tabaret
'upholstery fabric' is the definition.
(I've seen this in another clue)
'tasteless stuff edging plain' is the wordplay.
'tasteless stuff' becomes 'tat' (tat can mean worthless or tacky items).
'edging' means one lot of letters goes inside another (some letters go round the edges of others).
'plain' becomes 'bare' (similar in meaning).
'tat' enclosing 'bare' is 'TABARET'.
(Other definitions for tabaret that I've seen before include "material" , "Beat tar out of upholsterer's silk fabric" .)