Use toilet humour at first comedically in basic sketch? (10)
I believe the answer is:
silhouette
'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 silhouette that I've seen before include "Outline representation" , "Profile of characters" , "image" , "Outline figure" , "Shadowy outline" .)