Watch shillings coming in (6)
I believe the answer is:
sentry
'watch' is the definition.
(synonyms)
'shillings coming in' is the wordplay.
I cannot quite understand how this works, but
'shillings' could be 's' (abbreviation e.g. Lsd - pounds, shillings, pence) and 's' is located in the answer.
The remaining letters 'entry' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
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" .)