Greta's short dress (4)
I believe the answer is:
garb
'dress' is the definition.
('garb' can be a synonym of 'dress')
'greta's short' is the wordplay.
'greta' becomes 'garbo' (Greta Garbo).
'short' means to remove the last letter.
'garbo' with its final letter removed is 'GARB'.
(Other definitions for garb that I've seen before include "Kit" , "Attire, clothing" , "Apparel, attire" , "Dress - habit" , "costume" .)