Watch shillings coming in (6)
I believe the answer is:
sentry
'watch' is the definition.
(synonyms)
'shillings coming in' is the wordplay.
I cannot really see how this works, but
'shillings' could be 's' (abbreviation e.g. Lsd - pounds, shillings, pence) and 's' is found in the answer.
The remaining letters 'entry' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sentry that I've seen before include "Mil. guard" , "Watchperson" , "Person standing watch" , "Sentinel, watch" , "Guard on watch" .)