Posted racy bands to the watch man (6)
I believe the answer is:
sentry
'the watch man' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'posted racy bands' is the wordplay.
'posted' becomes 'sent' ('send' can be a synonym of 'post').
'racy bands' becomes 'ry' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'sent'+'ry'='SENTRY'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for sentry that I've seen before include "Mil. guard" , "Watchman" , "One keeps watch" , "One keeps guard" , "Lookout soldier" .)