Sit around old town quietly, almost completely determined (10)

I believe the answer is:

purposeful

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'determined' is the definition.
(synonyms)

'sit around old town quietly almost completely' is the wordplay.
I cannot quite see how this works, but
'sit' could be 'pose' (synonyms) and 'pose' is located in the answer.
'quietly' could be 'p' (p for piano and quiet) and 'p' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

(Another definition for purposeful that I've seen is " Intentional".)

I've seen this clue in the Sydney Morning Herald.

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