Supple, graceful (7)
I believe the answer is:
lissome
This clue is a double definition.
'supple' is the first definition.
(I know that supple can be written as lissome)
'graceful' is the second definition.
(similar in meaning)
(Other definitions for lissome that I've seen before include "Slim, supple, graceful" , "pliable" , "Thin - supple - graceful" , "Moving supply" , "flexible" .)