He doesn't believe he needs endless capital (7)
I believe the answer is:
heathen
'he doesn't believe he' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'needs endless capital' is the wordplay.
'needs' becomes 'he' (I can't explain this - if you can you should give a lot more credence to this answer).
'endless' means to remove the last letter.
'capital' becomes 'Athens' (capital of Greece).
'athens' with its last letter taken away is 'athen'.
'he'+'athen'='HEATHEN'
Can you help me to learn more?
(Other definitions for heathen that I've seen before include "Person lacking culture or moral principles" , "Godless person" , "Savage" , "Uncultured" , "Non-religious person" .)