Swearing about American rat (7)

I believe the answer is:

cussing

'swearing' is the definition.
('cuss' can be a synonym of 'swear')

'about american rat' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa').
'american' becomes 'US' (abbreviation for United States).
'rat' becomes 'sing' (both can mean to inform on someone).
'c'+'us'+'sing'='CUSSING'

I've seen this clue in The Telegraph.

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