He keeps still being a man of spirit (9)
I believe the answer is:
distiller
'he keeps still being a man of spirit' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he keeps still' is the wordplay.
'he' becomes 'dier' (I can't explain this - if you can you should give a lot more credence to this answer).
'keeps' indicates putting letters inside.
'dier' enclosing 'still' is 'DISTILLER'.
Can you help me to learn more?
(Other definitions for distiller that I've seen before include "Eg, whisky producer" , "One producing alcohol" , "Spirits manufacturer" , "Whisky manufacturer" , "a person of strong spirit" .)