Sew tear ruining garment (7)

I believe the answer is:

sweater

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

'garment' is the definition.
(sweater is a kind of garment)

'sew tear ruining' is the wordplay.
'sew tear' can be anagrammed to 'SWEATER'.
Though, I'm not clear how this is indicated.

Can you help me to learn more?

(Other definitions for sweater that I've seen before include "Jumper or jersey" , "mugger once" , "Top" , "Wear" , "Jersey may become" .)

I've seen this clue in The Sun.

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