'nonproteinaceous' originates from combining the prefix 'non-' (from Old English 'nān' via ME 'non', meaning 'not') and the adjective 'proteinaceous', itself formed from 'protein' + the suffix '-aceous'. 'protein' ultimately comes from Greek 'proteios' meaning 'primary' or 'of first importance'.

'protein' was coined in the 19th century from Greek 'proteios'; from that emerged the adjective 'proteinaceous' by adding the Latin-derived adjectival suffix '-aceous'; later the negative prefix 'non-' was attached to form 'nonproteinaceous'.

Initially 'protein' referred to the primary substance (from Greek), and with affixation it came to mean 'related to or containing protein'; 'nonproteinaceous' evolved to mean 'not containing or composed of protein'.