'archagitator' originates from Greek and Latin elements, specifically the Greek prefix 'arkhi-' (as 'arch-') meaning 'chief' combined with the Latin verb 'agitare' (via English 'agitator') meaning 'to drive, stir, or agitate'.

'archagitator' changed from the compound form 'arch-' + 'agitator' (earlier seen in forms like 'arch-agitator') and eventually became the modern English word 'archagitator'.

Initially, it meant 'a chief stirrer or chief mover', but over time it evolved into the current meaning of 'a principal instigator, especially of political protest or unrest'.