'astoundment' originates from English, specifically formed from the verb 'astound' plus the nominal suffix '-ment', where the suffix '-ment' meant 'action or resulting state'.

'astound' changed from Middle English 'astounen' (from Old French 'estoner'), which in turn comes from Latin roots related to 'tonare' meaning 'to thunder'; the Modern English noun 'astoundment' was later formed by adding '-ment' to 'astound'.

Initially the root idea was 'to stun or strike (as if by thunder)', but over time it evolved into the sense 'to greatly surprise'; the noun 'astoundment' therefore means 'the state of being greatly surprised'.