mend (a hole in knitted material) by interweaving yarn with a needle

I don't expect you to darn my socks

a place in a garment that has been darned

a sweater with darns in the elbows

used to emphasize something, especially to express anger or frustration

he was a darn sight younger than Jill

the darn things were expensive

winning it didn't mean a darned thing

you're darn right it's up to me!

used for emphasis, especially to express anger or frustration

darn, I missed the show

used in various expressions for emphasis or to express anger or frustration

darn it all, Poppa!