One who plays at work (5)
I believe the answer is:
actor
'one who plays at work' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for actor that I've seen before include "Thespian, stage performer" , "Stage-player" , "Cruise, e.g." , "Performer in drama" , "Croat (anag.)" .)