Reveals it to be flexible (9)
I believe the answer is:
versatile
'flexible' is the definition.
('versatile' can be similar in meaning to 'flexible')
'reveals it to be' is the wordplay.
'to be' indicates anagramming the letters.
'reveals'+'it'='revealsit'
'revealsit' anagrammed gives 'VERSATILE'.
(Other definitions for versatile that I've seen before include "willing to fit in?" , "Good at many things" , "Adaptable like relatives" , "Capable of many functions" , "Adapting easily to different tasks" .)