'flesh-eater' originates from English, formed as a compound of 'flesh' and the agentive 'eater'; 'flesh' comes from Old English 'flǣsc' meaning 'meat', and 'eat' comes from Old English 'etan' meaning 'to eat'.

'flesh' developed from Old English 'flǣsc' (Middle English 'flesch'/'fles') and 'eat' from Old English 'etan' (Middle English 'geten'/'eten'); the agentive suffix '-er' produced 'eater', and these elements combined into the modern compound 'flesh-eater'.

Initially it meant 'one who eats flesh (meat)' in a literal, descriptive sense; over time the term retained that core meaning but also acquired specialized senses (e.g., 'cannibal') and figurative uses for ruthless or exploitative people.