Comedian's repertoire is one that's absurd (8,5)
I believe the answer is:
'comedian's' is the definition.
Both the answer and definition are singular nouns.
Perhaps they are linked in a way I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for laughing stock that I've seen before include "Object of ridicule" , "inhabitants of funny farm?" , "Target of ridicule" , "Butt of ridicule" , "Object to joke" .)