'archknave' is formed from the prefix 'arch-' (from Greek 'arkhos' via Latin/Old French, meaning 'chief, principal') + 'knave' (from Old English 'cnafa', meaning 'boy, servant').

'arch-' (Greek 'arkhos' → Late Latin/Old French 'arch-') combined with Old English 'cnafa' (later 'knave') in Middle English to form the compound 'archknave', used to denote a principal knave or extreme rogue.

Initially it carried the sense 'principal servant' or 'chief knave' (often with neutral or occupational connotations for 'knave'), but over time it came to mean 'principal rogue' or 'arch-villain' with strongly negative connotations.