'anti-lynch' originates from the English prefix 'anti-' (from Greek 'anti', meaning 'against') combined with 'lynch' (from the proper name 'Lynch', associated with 'lynch law' and the verb 'to lynch').

'lynch' arose in American English in the late 18th century as part of the phrase 'Lynch's law' (attributed to a person named Lynch) and developed into the verb 'to lynch' meaning extrajudicial killing; the prefix 'anti-' was later attached (19th–20th century) to form terms like 'anti-lynch' and more commonly 'anti-lynching'.

Initially it referred specifically to opposition to 'Lynch's law' or particular acts labeled as lynching, and over time it broadened to mean general opposition to the practice of lynching and related forms of mob violence.