'nonpsychological' originates from Modern English, formed by prefixing 'non-' (from Latin 'non' meaning 'not') to 'psychological', which ultimately derives from Greek 'psyche' meaning 'soul, mind' and Greek element '-logia' meaning 'study'.

'psychological' entered English via Neo-Latin 'psychologia' and French 'psychologique' (and Medieval/early modern usages of related forms) and became the English adjective 'psychological'; the prefix 'non-' was later attached in Modern English to create 'nonpsychological'.

Originally 'psychological' meant 'relating to the study of the mind' (from 'psyche' + 'logia'); over time it came to mean 'relating to mental or emotional processes,' and with the prefix 'non-' the compound now means 'not relating to mental processes'.