'antipopulationist' originates from modern English, specifically formed by the prefix 'anti-' (from Greek 'anti-' meaning 'against'), the noun 'population' (from Latin via Old French), and the agent suffix '-ist' (from Greek/Latin/English) denoting a person who adheres to a position.

'population' derives from Latin 'populatio' (related to 'populus' meaning 'people'), passed into Old French as 'population' and into Middle English before becoming the modern English 'population'. The element 'anti-' comes from Greek 'anti-' meaning 'against' and has been widely used in English compounds since the 17th–19th centuries; the suffix '-ist' is used in English to form agent nouns from nouns and adjectives.

The compound originally names someone "against population" in a literal compositional sense; over time it is used specifically to mean someone opposed to population growth or to policies promoting higher population, a nuance consistent with its component parts.