Versatile, flexible (9)
I believe the answer is:
adaptable
I believe this is a double definition.
'versatile' is the first definition.
(I've seen this before)
'flexible' is the second definition.
(similar in meaning)
(Other definitions for adaptable that I've seen before include "Open to modification" , "Good at fitting in to new situations" , "Flexible, pliant" , "Happy to fit in" , "Able to be modified" .)