His accounts are not taken seriously (5)
I believe the answer is:
comic
'his accounts are not taken seriously' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is the entire clue.
Can you help me to learn more?
(Other definitions for comic that I've seen before include "Professional funny person" , "Victor once, say" , "Funny entertainer, often stand-up" , "Funny, laughable" , "publication for children" .)