'antimonopoly' originates from Modern English, formed by the prefix 'anti-' (from Greek anti- 'against') combined with the noun 'monopoly' (ultimately from Greek 'monopolion', from 'monos' 'single' + 'polein' 'to sell').

'antimonopoly' was created in Modern English by combining 'anti-' + 'monopoly'. The element 'monopoly' entered English via Late Latin 'monopolium' and Old French/French 'monopole', derived from Greek 'monopolion', and later combined with the productive prefix 'anti-' in modern political/economic usage.

Initially it literally meant 'against monopoly'; over time it has come to refer more specifically to laws, policies, or official measures (i.e., antitrust/competition law and regulation) aimed at preventing monopolies.