Small swimsuit (6)
I believe the answer is:
bikini
'small swimsuit' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for bikini that I've seen before include "Small bathing costume or atoll in Marshall Islands" , "Brief two-piece swimming costume" , "Minuscule bathing costume for woman" , "Pacific atoll, used for US nuclear weapons tests" , "Skimpy two-piece swim wear" .)