'prefebrile' originates from Latin, specifically the elements 'prae-' and 'febris', where 'prae-' meant 'before' and 'febris' meant 'fever'.

'febrile' comes from Latin 'febrilis' (from 'febris' meaning 'fever'); English formed 'febrile' from Old French/Latin influence, and 'prefebrile' (or 'pre-febrile') is formed in English by adding the prefix 'pre-' (from Latin 'prae-') to 'febrile'.

Initially, the Latin elements referred literally to 'before fever'; in English the combined adjective has retained that specific medical sense of 'occurring before a fever'.