'unfittingly' originates from the English prefix 'un-' meaning 'not' and the word 'fitting,' which comes from the Old English 'fittan,' meaning 'to fit or be suitable.'

'fitting' changed from the Old English word 'fittan' and eventually became the modern English word 'fitting.' The prefix 'un-' was added to form 'unfitting,' and the adverbial suffix '-ly' was added to form 'unfittingly.'

Initially, 'fitting' meant 'to be suitable or appropriate,' and 'unfittingly' evolved to mean 'in a manner that is not suitable or appropriate.'