Left light show (7)
I believe the answer is:
portray
'show' is the definition.
(I've seen this before)
'left light' is the wordplay.
'left' becomes 'port' (left side of a ship - opposite of starboard).
'light' becomes 'ray' (ray is a kind of light).
'port'+'ray'='PORTRAY'
(Other definitions for portray that I've seen before include "sketch" , "Describe in words or make a picture" , "Depict in art" , "Act" , "Show" .)