'astony' originates from Anglo-French (Old French) roots related to 'estoner', ultimately from Vulgar Latin *extonare, where 'ex-' meant 'out' and 'tonare' meant 'to thunder'.

'astony' changed from Old French forms such as 'estonie' / 'estoner' into Middle English 'astonie' and eventually into the rare modern English form 'astony' (plural 'astonies').

Initially it meant 'to be thunderstruck' or 'a state of being struck (as by thunder)', and over time it came to mean 'astonishment' or 'amazement'; the word is now archaic and largely replaced by 'astonishment'.