Perform in plays (3)
I believe the answer is:
act
'perform in plays' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for act that I've seen before include "Take part in a play" , "Behave like thespian" , "Bill successfully prosecuted" , "Perform theatrically" , "Perform - part of a play" .)