십년감수가 · 십년감수를 (often 십년감수했어요)
being scared half to death, a close call (lit. losing ten years of one's life)
Example
갑자기 차가 튀어나와서 정말 십년감수했어요.
A car suddenly darted out, and it scared the life out of me.
Word parts
십 ten+년 year+감 reduce+수 lifespan
Literally 'ten years cut from one's lifespan' — a fright so bad it feels like it shortened your life.
Good to know
Pronounced [심년감수]. Said right after a near miss: 아이고, 십년감수했네!