'unskillfully' originates from the prefix 'un-' meaning 'not' and the word 'skillful,' which comes from the Old Norse word 'skil' meaning 'discernment.'

'unskillful' changed from the Old English word 'unscylful' and eventually became the modern English word 'unskillful.'

Initially, it meant 'lacking skill or proficiency,' and this meaning has largely remained the same in modern usage.