Daft trap for one using foul language (5,5)

I believe the answer is:

potty mouth

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'foul language' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'daft trap for one' is the wordplay.
'daft' becomes 'potty' (I've seen this in another clue).
'trap for one' becomes 'mouth' (trap is a kind of mouth).
'potty'+'mouth'='POTTY MOUTH'

'using' acts as a link.

Can you help me to learn more?

I've seen this clue in The Guardian.

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