Sketch show uses nonessential revenue (5)
I believe the answer is:
revue
'sketch' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for revue that I've seen before include "Topical variety show" , "Variety show with mixed entertainments" , "(Of butter) tasting off" , "Theatrical show" , "Show of sketches, songs, etc" .)