noun
letting die without helping; standing by while someone dies
Implies a moral failure to act; often used in serious contexts such as accidents, crimes, or social issues.
事故現場で見殺しにするなんて許せない。
It's unforgivable to just stand by and let someone die at an accident scene.
彼は溺れている人を見殺しにしたと非難された。
He was accused of letting the drowning person die without helping.