One who goes down as a deceiver of referees? (5)
I believe the answer is:
diver
This could be a double definition.
'one who goes down as a' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'deceiver of referees?' is the second definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
Can you help me to learn more?
(Other definitions for diver that I've seen before include "Bird that plunges" , "One jumping off board" , "Large waterbird" , "Competitor in pool" , "Grebe maybe" .)