'unnaturally' originates from the word 'unnatural', which is derived from the Latin word 'innaturalis', where 'in-' meant 'not' and 'naturalis' meant 'natural'.

'innaturalis' transformed into the Old French word 'unnaturel', and eventually became the modern English word 'unnatural' through Middle English.

Initially, it meant 'not natural', and this meaning has largely remained the same in modern usage.