He keeps a servant (8)
I believe the answer is:
retainer
'servant' is the definition.
(synonyms)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for retainer that I've seen before include "Long-standing family servant" , "Eritrean (anag)" , "Fee paid to secure services" , "reduced rent" , "Household servant (often faithful and old!)" .)