'aswirl' originates from the prefix 'a-' (ultimately from Old English 'on', meaning 'in' or 'at') combined with the word 'swirl' (from Middle English 'swirlen'), where 'a-' meant 'in' and 'swirl' meant 'to move in a twisting or spiraling motion.'

'aswirl' developed from Middle English combinations of the prefix 'a-' plus verbs like 'swirlen' (and related dialectal forms such as 'awhirl'), and through regularization and loss of older inflections it became the modern English word 'aswirl.'

Initially it meant 'in a swirling or whirling state' in a literal, physical sense; over time it retained that literal sense and also acquired a figurative sense meaning 'filled with activity, excitement, or rumor.'