Begin to understand (6,2)

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6,2

cotton on

'begin to understand' is the definition.
(I've seen this before)

This is all the clue.

(Other definitions for cotton on that I've seen before include "Downy fibre attached to" , "Come to understand" , "Get wise (to)" , "Understand (slang)" , "what a cool dresser has, perhaps" .)

I've seen this clue in The Guardian.

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