He loves sport (7)
I believe the answer is:
amateur
This might be a double definition.
'he' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'loves sport' is the second definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's a link between them I don't understand?
Can you help me to learn more?
(Other definitions for amateur that I've seen before include "incompetent" , "Unpaid (sportsman}" , "enthusiast" , "unskilful" , "He's not professional" .)