Customs raid -- it's not unusual (10)

I believe the answer is:

traditions

'customs' is the definition.
('tradition' can be a synonym of 'custom')

'raid it's not unusual' is the wordplay.
'unusual' indicates anagramming the letters.
'raid'+'its'+'not'='raiditsnot'
'raiditsnot' is an anagram of 'TRADITIONS'.

(Another definition for traditions that I've seen is " Customs".)

I've seen this clue in The Telegraph.

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