1
general::
Also, spill blood. Wound or kill someone, especially violently. For example, It was a bitter fight but fortunately no blood was shed, or A great deal of blood has been spilled in this family feud. Both of these terms allude to causing blood to flow and fall on the ground. The first dates from the 1200s. The variant amplifies the verb spill, which from about 1300 to 1600 by itself meant "slay" or "kill"; it was first recorded about 1125.
American Heritage Idioms