Become the worse for wear due to fighting? (4)

I believe the answer is:

fray

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'to fighting?' is the definition.
(fray is a kind of fighting)

I don't understand the remainder of the clue.

(Other definitions for fray that I've seen before include "Conflict; wear at edges" , "Show effects of strain" , "Become stressed" , "Rub off, unravel" , "Chafe" .)

I've seen this clue in the Evening Standard.

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