What does “손절” mean in Korean slang?

손절 started in stock trading as 손절매, selling a falling stock at a loss so it can’t fall further. Koreans now use it for people: 손절하다 means to drop a friend, an ex or a relative you’ve decided is not worth the trouble. It carries the same cold logic as the stock term: you’ve counted the cost, and you’re out. It is casual slang, not something you would say to your boss.

The clip’s caption sets up a grandfather whose granddaughter’s boyfriend has come to cook for him: 할아버지가 엄청난 걸 봐버렸습니다. Then comes 순간 정적이 흐르는 부엌 (“a silence falls in the kitchen”) and the punchline, 그리고 빠르게 손절하시는 할아버지, “and grandpa cuts him off, fast.” The -시- in 손절하시는 is the honorific: the joke is dry, but the verb still respects the grandfather.