'inequally' originates from Latin, specifically the word 'inaequalis', where 'in-' meant 'not' and 'aequalis' meant 'equal'.

'inequally' changed from Middle English/Old French forms such as Middle English 'inequal' and Old French 'inegal', and eventually became the modern English adverb 'inequally' by adding the adverbial suffix '-ly'.

Initially it meant 'not equal' (literal lack of equality), but over time it has come to be used commonly in contexts implying 'unfairly' or 'disproportionately'.