Learns to fit in (6)
I believe the answer is:
adapts
'learns to fit in' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for adapts that I've seen before include "Converts to another use or purpose" , "Changes to suit new circumstances" , "Modifies for a new use" , "Changes to fit new circumstances" , "Changes to suit another purpose" .)