He keeps a servant (8)

I believe the answer is:

retainer

I'm a little stuck... Click here to teach me more about this clue!

'servant' is the definition.
(synonyms)

I can't explain the remainder of the clue.

(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!)" .)

I've seen this clue in The Globe and Mail.

Want a hint initially instead of a full solution? Install my app