One who has a strong hand in clubs (7)
I believe the answer is:
bouncer
'one who has a strong hand in clubs' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'one who has a strong hand in clubs' is the wordplay.
I cannot really understand how this works, but
'one' could be 'un' (northern English dialect form of 'one') and 'un' is present in the answer.
'hand' could be 'r' (abbreviation for right, as in the right-hand side) and 'r' is found in the answer.
'clubs' could be 'c' (abbreviation used in card games such as bridge) and 'c' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for bouncer that I've seen before include "Club doorkeeper" , "Security man outside night-club, or a rubber ball" , "cheque that's worthless?" , "Club employee" , "Bumper" .)