삐끗 is an adverb describing the following situations:
1. two things going out of alignment (창문이 칭틀에서 삐끗 어긋났다 - The window is out of line with the frame).
2. an arm, leg, or some other part spraining (팔을 삐끗 삐었다 - I forced my arm the wrong way and sprained it).
3. something going wrong in general (여기선 발 한번 삐끗하면 낭떠러지다 - Here, one wrong step and you fall all the way).