Number Ten okay about charlatanism (13)

I believe the answer is:

mountebankery

'charlatanism' is the definition.
(I know that charlatanism can be written as mountebankery)

'number ten okay about' is the wordplay.
'about' indicates an anagram.
'number'+'ten'+'okay'='numbertenokay'
'numbertenokay' with letters rearranged gives 'MOUNTEBANKERY'.

(Another definition for mountebankery that I've seen is " Quackery".)

I've seen this clue in The Independent.

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