'archcharlatan' originates from a combination of the prefix 'arch-' (from Greek 'archi-'/'arkhē') meaning 'chief, principal' and the word 'charlatan' (from Italian 'ciarlatano'), where 'ciarlare' meant 'to chatter, prate'.

'charlatan' entered English from Italian 'ciarlatano' (via French 'charlatan') in early modern English; the intensifying prefix 'arch-' (from Greek via Latin) was later attached in English formation to produce 'archcharlatan' as a compound meaning a chief or extreme charlatan.

Initially, 'charlatan' referred to a chatterer or mountebank (a seller of quack medicines); over time it came to mean any impostor posing as an expert, and the compound 'archcharlatan' developed the intensified meaning 'the foremost or most egregious impostor'.