'non-febrile' originates from Latin, specifically the word 'febrilis,' where 'febris' meant 'fever.' The prefix 'non-' indicates the absence of fever.

'febrilis' transformed into the English word 'febrile,' and with the addition of the prefix 'non-,' it became 'non-febrile.'

Initially, it meant 'without fever,' and this meaning has largely remained the same in modern usage.