A light amusing play or film (6)
I believe the answer is:
comedy
'a light amusing play or film' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for comedy that I've seen before include "Humorous film/play" , "Play with two sets of twins" , "Form of light entertainment" , "Humorous play, film" , "kind of play" .)