Habit of being contrary? (4)

I believe the answer is:

wont

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'habit' is the definition.
(I know that habit can be written as wont)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for wont that I've seen before include "Succinct refusal" , "Is not going to" , "Habit" , "normal practice" , "customary behaviour" .)

I've seen this clue in the Evening Standard.

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