'appallment' originates from English, specifically from the verb 'appall' + the noun-forming suffix '-ment', where 'appall' ultimately comes from Old French 'apalir' meaning 'to grow pale (with fear)'.

'appall' changed from Old French 'apalir' (from Vulgar/Latin roots related to Latin 'pallescere' meaning 'to grow pale'), later becoming Middle English 'appallen' and modern English 'appall'; the noun 'appallment' was formed by adding '-ment' to the verb.

Initially it meant 'to make pale (with fear)', but over time it evolved into the current sense of 'to horrify or greatly shock,' and 'appallment' denotes the resulting state of shock or dismay.