'aghast' originates from Middle English, specifically the word 'agasten,' where 'a-' meant 'intensive' and 'gasten' meant 'to frighten.'

'agasten' transformed into the modern English word 'aghast' through Middle English.

Initially, it meant 'to be terrified or frightened,' but over time it evolved into its current meaning of 'filled with horror or shock.'