'blood-money' is a compound of English 'blood' and 'money'; 'blood' comes from Old English 'blōd', and 'money' comes via Old French 'moneie' from Latin 'moneta'.

'blood-money' developed in Middle English as a literal compound meaning money relating to bloodshed (compensation or payment). The idea echoes older Germanic concepts such as the Old English/Old Norse 'wergild' ('man-price'), while the word 'money' entered English via Old French and Latin.

Originally it referred primarily to compensation paid in cases of killing (akin to 'wergild'); over time it also acquired the additional sense of payment made as a reward for committing a killing or as a bribe to conceal a crime.