'antidisestablishmentarian' originates from English political coinage combining prefix 'anti-' (from Greek 'anti-' meaning 'against'), the element 'dis-' (from Latin 'dis-' meaning 'apart, not'), 'establishment' (from Old French/Latin meaning 'a setting up, institution'), and the suffix '-arian' (from Latin '-arius' meaning 'pertaining to' or 'connected with').

'antidisestablishmentarian' developed in 19th-century England from the phrase 'anti-disestablishment' (opposition to disestablishing the Church of England) with the addition of the agent/relational suffix '-arian' to denote a person or stance, eventually forming the modern single-word use.

Initially it referred specifically to political opponents of disestablishing the Church of England; over time it became a general term (and a lexical curiosity) meaning 'one opposed to disestablishment' and is now often cited as an example of a long English word.