He looks fishier than he sounds (4)
I believe the answer is:
bass
This clue could be a double definition.
'he looks fishier' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he sounds' is the second definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'than' acts as a link.
Can you help me to learn more?
(Other definitions for bass that I've seen before include "Big percussion instrument" , "Male singer and saltwater fish" , "deep in the sound" , "part of score" , "Fish; deep voice" .)