'astonisher' originates from 'English', specifically the word 'astonish', where 'astonish' comes from Old French 'estoner' and Late Latin 'extonare', and the element 'tonare' meant 'to thunder'.

'astonish' changed from Old French 'estoner' (from Late Latin 'extonare') into Middle English 'astonish', and the agentive suffix '-er' was later added to form the noun 'astonisher'.

Initially, the root meant 'to strike or thunder' (a sense of being stunned), but over time it evolved into the current sense 'to surprise greatly', with 'astonisher' meaning 'one who causes great surprise'.