'antivariolous' originates from the prefix 'anti-' (from Greek 'anti-' meaning 'against') combined with the Latin word 'variola' meaning 'smallpox', producing an adjective meaning 'against smallpox'.

'antivariolous' developed by prefixing 'anti-' to the established adjective 'variolous' (from Latin 'variola'), forming the compound adjective used in medical and public-health texts in the 18th–19th centuries.

Initially, it meant 'acting against or preventing smallpox' and that core meaning has largely remained, though the term is now rare or archaic and largely of historical interest.