See idiot rant about custom (9)

I believe the answer is:

tradition

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'custom' is the definition.
(synonyms)

'see idiot rant' is the wordplay.
'idiot rant' anagrams to 'TRADITION'.
However, I'm not clear how the anagram is indicated.

'about' acts as a link.

Can you help me to learn more?

(Other definitions for tradition that I've seen before include "Transmitted customs" , "Inherited custom" , "Established usage" , "Body of beliefs and customs handed down through generations" , "Customs etc handed down" .)

I've seen this clue in The Mirror.

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