What one should do for payment? (4)
I believe the answer is:
duty
'payment?' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'what one should do' is the wordplay.
I cannot quite understand how this works, but
'do' could be 'ut' (synonyms) and 'ut' is present in the answer.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for duty that I've seen before include "Moral or legal obligation" , "Not subject to customs tax" , "Moral/legal obligation" , "form of tax" , "Government tax" .)