Behaved (5)
I believe the answer is:
acted
'behaved' is the definition.
('act' can be a synonym of 'behave')
This is the entire clue.
(Other definitions for acted that I've seen before include "Feigned" , "participated in panto maybe" , "Behaved in a certain manner" , "Play a role" , "Behaved or played a part" .)