Color-changing lizard (9)
I believe the answer is:
chameleon
'color-changing lizard' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for chameleon that I've seen before include "Lizard that can change its colours" , "person who's changeable" , "It blends" , "Person who keeps changing" , "Someone who changes position to suit the situation" .)