noun
bloody vomit
Refers to vomit containing blood, often from internal injury or severe illness. Can be used literally or figuratively to describe extreme effort or suffering.
彼は血反吐を吐くような思いで仕事を終えた。
He finished the work with an effort that felt like vomiting blood.
事故の後、血反吐が出た。
After the accident, he vomited blood.
Compound of 血 (blood) and 反吐 (vomit). The exact historical derivation is uncertain, but the word is conventionally associated with the meaning of bloody vomit.