Take apart idlest man for thrashing (9)

I believe the answer is:

dismantle

I'm a little stuck... Click here to teach me more about this clue!

'take apart' is the definition.
(I know that take apart can be written as dismantle)

'idlest man for thrashing' is the wordplay.
'idlest man' anagrams to 'DISMANTLE'.
But, I'm not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for dismantle that I've seen before include "Take to pieces" , "Pull to pieces" , "Strip down" , "Unrig" , "Take apart" .)

I've seen this clue in The Times.

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