'antilynching' originates from English elements: the prefix 'anti-' (from Greek 'anti-' via Latin/French, meaning 'against') combined with 'lynching' (from the verb 'lynch').

'lynch' developed in late 18th-century American English from the phrase 'Lynch's law' (attributed to the surname 'Lynch'), became the verb 'lynch' meaning 'to execute without legal trial,' which produced the noun 'lynching'; the prefix 'anti-' was later attached to form 'anti-lynching' and the single-word variant 'antilynching'.

Initially, 'Lynch's law' referred to extrajudicial punishments associated with a specific name/family, and 'lynching' came to mean mob execution; over time 'anti-lynching' evolved to denote opposition to that practice and the campaigns to criminalize or prevent it.