Faster fastener needed on the wharf (7)

I believe the answer is:

zippier

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'faster' is the definition.
Both the answer and definition are comparative adjectives. Maybe they are linked in a way I don't understand?

'fastener needed on the wharf' is the wordplay.
'fastener' becomes 'zip' (zip is a kind of fastener).
'needed on' is a charade indicator (letters next to each other) (in a down clue, some letters go on top of others).
'the wharf' becomes 'pier' (I've seen this before).
'zip'+'pier'='ZIPPIER'

Can you help me to learn more?

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

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