Furnish with flexibility (6)
I believe the answer is:
supply
I believe this clue is a double definition.
'furnish' is the first definition.
(I know that furnish can be written as supply)
'with flexibility' is the second definition.
(in a supple way)
(Other definitions for supply that I've seen before include "Contribute" , "Give" , "store" , "Furnish goods or services" , "in flexible way" .)