Crude at slander (7)

I believe the answer is:

traduce

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'slander' is the definition.
(I know this)

'crude at' is the wordplay.
'crude at' can be anagrammed to 'TRADUCE'.
But, I am not sure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for traduce that I've seen before include "Speak badly of" , "Misrepresent in unfavourable way" , "'Malign, badmouth (7)'" , "Calumniate" , "Malign -- rude act (anag)" .)

I've seen this clue in The Irish News.

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