'avaunt' originates from Old French, specifically the word 'avant', where 'avant' meant 'forward' or 'before' (used to indicate movement away or to the front).

'avaunt' changed from Anglo-Norman/Middle English forms such as 'avaunten' and 'avaunt' (imperative/verb usage) and entered Modern English as the archaic exclamation and verb 'avaunt'. The Old French 'avant' itself reflects earlier Latin influence (compare Latin 'ante' meaning 'before').

Initially it conveyed the sense of 'forward' or 'in front of'; over time it developed into an imperative sense 'begone!' and a verb sense 'to drive away', now largely archaic.