Swear to sew up holes in clothes (4)

I believe the answer is:

darn

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But I can't explain it at all! Could you help me understand?

(Other definitions for darn that I've seen before include "Repair holes by sewing" , "Repair with wool" , "Mend with stitches" , "Sew" , "Mild oath; repair (socks)" .)

I've seen this clue in The Hindu.

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