'antiinstitutionalist' originates from two main parts: the prefix 'anti-' from Greek 'anti' meaning 'against', and 'institution' from Latin 'institutio' (from 'instituere') meaning 'to set up' or 'establish', combined with the agent-forming suffix '-ist' (via Modern English/French).

'Institution' came into English via Old French 'institution' from Latin 'institutio'. The adjectival/noun forms 'institutional' and 'institutionalist' were formed in Modern English; 'antiinstitutionalist' is a compound formed by adding the prefix 'anti-' to 'institutionalist' in Modern English (19th–20th century usage patterns for political/social descriptors).

Initially the elements meant 'against' + 'established set-up'; over time the compound has retained this core sense and is used to describe persons or attitudes opposing institutions or institutionalism, especially in political or social contexts.