'archdogmatist' originates from the combining form 'arch-' (from Greek 'arkhē/arkhos') and 'dogmatist' (via Greek 'dogma'), where 'arkhē/arkhos' meant 'chief, principal' and 'dogma' meant 'opinion, decree'.

'arch-' has been used in English since medieval/early modern periods as a prefix meaning 'principal' (compare 'archbishop'), while 'dogma' entered English via Latin and Greek; 'dogmatist' developed as a derivative meaning 'one who holds or asserts dogma,' and the compound 'archdogmatist' is a later rhetorical/derivative formation in modern English to denote an especially prominent or extreme dogmatist.

Initially the elements separately denoted 'chief' and 'opinion/doctrine'; combined as 'archdogmatist' the term evolved to mean 'the foremost or most extreme proponent of a rigid doctrine,' often with a pejorative connotation.