'archmugwump' originates from English, formed from the prefix 'arch-' (via Greek 'arkhos', meaning 'chief') and 'mugwump', which ultimately comes from an Algonquian word.

'archmugwump' developed as a compound after the political use of 'mugwump' in the late 19th century (notably U.S. politics c.1884); 'mugwump' itself traces back to Algonquian 'mugquomp' (recorded in early New England English) meaning 'important person' or 'war leader', and the modern compound added 'arch-' to indicate a chief or extreme example.

Initially, the root (Algonquian) sense meant 'important person' or 'leader'; in English 'mugwump' shifted to a jocular/political sense of an independent or aloof person, and 'archmugwump' came to mean the chief or most extreme example of such a person (sometimes used ironically to mean a pompous figure).