Am in act noted perhaps for being filthy (12)

I believe the answer is:

contaminated

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

'am in act noted perhaps' is the wordplay.
'perhaps' indicates anagramming the letters.
'am'+'in'+'act'+'noted'='aminactnoted'
'aminactnoted' anagrammed gives 'CONTAMINATED'.

'for' is the link.

Can you help me to learn more?

(Other definitions for contaminated that I've seen before include "Bad" , "Polluted - anatomic dent (anag)" , "Made impure" , "infected" , "No longer pure" .)

I've seen this clue in The Globe and Mail.

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