'antivaccinist' originates from Modern English, specifically from the combination of the prefix 'anti-' (from Greek 'anti-' meaning 'against') and 'vaccinist', which is derived from 'vaccine' (ultimately from Latin 'vaccinus' related to 'vacca' meaning 'cow').

'vaccinist' is built on 'vaccine', which comes from New Latin 'vaccina' and Latin 'vaccinus' ('of a cow') from 'vacca' ('cow'); 'antivaccinist' was formed in English by adding the prefix 'anti-' to denote opposition to vaccination.

Initially, 'vaccine' referred to material from cows (cowpox) used for inoculation; over time the terms around 'vaccine' broadened to mean immunization more generally, and 'antivaccinist' developed to mean someone opposed to vaccines or vaccination policy.