Short dress (4)
I believe the answer is:
mini
'short dress' is the definition.
(I have seen 'Short dress' mean 'mini' so perhaps 'dress' could also mean 'mini'; 'short' asks for an abbreviation)
This is all the clue.
(Other definitions for mini that I've seen before include "Once fashionable skirt" , "vehicle" , "Iconic economy car (introduced in 1959)" , "type of garment" , "Baby" .)