Dress is lifted outside topless bar (4)
I believe the answer is:
sari
'dress' is the definition.
(I know that sari is a type of dress)
'is lifted outside topless bar' is the wordplay.
'lifted' is a reversal indicator (going up in down clue).
'outside' is an insertion indicator (some letters go outside others).
'topless' means to remove the first letter.
'is' backwards is 'si'.
'bar' with its first letter taken off is 'ar'.
'si' placed around 'ar' is 'SARI'.
(Other definitions for sari that I've seen before include "Asian dress" , "Traditional dress of Indian women" , "Indian costume" , "Eastern garment" , "habit" .)