He doesn't work as a bell-ringer (7)
I believe the answer is:
striker
'he doesn't' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'work as a bell-ringer' is the wordplay.
I cannot quite see how this works, but
'work' could be 'strike' (striking is a kind of working) and 'strike' is found in the answer.
A single letter 'r' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for striker that I've seen before include "Goalscorer" , "One refusing to work - rings the bell" , "disaffected employee" , "A forward on a soccer team" , "Attacking player" .)