Represses a subscription owing before first September (7)

I believe the answer is:

subdues

I'm a little stuck... Click here to teach me more about this clue!

'represses' is the definition.
('subdue' can be a synonym of 'repress')

'a subscription owing before first september' is the wordplay.
'a subscription' becomes 'sub' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'owing' becomes 'due' (similar in meaning).
'before' is a charade indicator (letters next to each other).
'first september' becomes 's' (sst letter of 'september').
'sub'+'due'+'s'='SUBDUES'

Can you help me to learn more?

(Another definition for subdues that I've seen is " Quietens, overcomes".)

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

Want a hint initially instead of a full solution? Install my app