'auntliest' originates from English, specifically formed from the noun 'aunt' (ultimately from Latin 'amita'), where 'amita' meant 'father's sister'; the English word then took the adjectival suffix '-ly' and the superlative suffix '-est'.

'auntliest' changed from Middle English forms such as 'aunte' (from Old French 'ante'), which became modern English 'aunt'; from 'aunt' the adjective 'auntly' was formed, and the regular superlative became 'auntliest'.

Initially the root 'amita' meant 'father's sister'; over time its descendants came to mean the familial role 'aunt' and then adjectival derivatives described characteristics 'like an aunt', with 'auntliest' meaning 'most like an aunt'.