'disestablishmentarian' originates from English, formed from the prefix 'dis-' (from Latin 'dis-' meaning 'apart' or 'reversal'), the noun 'establishment' (from Old French 'establir' / 'establissement', ultimately from Latin 'stabilis'/'stabilire' meaning 'firm' or 'to make firm'), and the suffix '-arian' (from Latin '-arius' meaning 'pertaining to' or 'one who').

'disestablishmentarian' developed in English by combining 'disestablishment' (the act or policy of removing an established church) with the adjectival/noun-forming suffix '-arian'; related forms such as 'disestablishmentarianism' arose in the 19th century in discussions about state churches and their status.

Initially it referred specifically to someone who opposed an established (state) church; over time the core meaning has remained stable and continues to denote support for removing official church establishment.