Firm editor acted as styptic (9)

I believe the answer is:

staunched

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'acted as styptic' is the definition.
I can't tell whether this defines the answer.

'firm editor' is the wordplay.
'firm' becomes 'staunch' (I've seen this in another clue).
'editor' becomes 'ed' (abbreviation).
'staunch'+'ed'='STAUNCHED'

Can you help me to learn more?

(Another definition for staunched that I've seen is " checked".)

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

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