Elastic hem of bikini caught in bush? (6)
I believe the answer is:
pliant
'elastic' is the definition.
(synonyms)
'hem of bikini caught in bush?' is the wordplay.
'hem of' suggests the final letters (hem can mean an edge or border).
'caught in' indicates putting letters inside.
'bush?' becomes 'plant' (bush is a kind of plant).
The final letter of 'bikini' is 'i'.
'i' inserted into 'plant' is 'PLIANT'.
(Other definitions for pliant that I've seen before include "Flexible, easily bent or influenced" , "Flexible and easily manipulated" , "Adaptable" , "Tractable" , "Plastic" .)