'nonintellectual' originates from English, specifically the prefix 'non-' (ultimately from Latin 'non') and the adjective 'intellectual', where 'non-' meant 'not' and 'intellectual' derived from Latin 'intellectus'/'intelligere' meaning 'to understand'.

'intellectual' passed into English via French 'intellectuel' from Latin 'intellectus' (past participle of 'intelligere'), and the negating prefix 'non-' has long been used in English to form negations; the compound 'nonintellectual' is a straightforward modern English formation combining those elements.

Initially it literally meant 'not intellectual' (simple negation); over time the phrase has retained that basic meaning but acquired usage nuances (neutral descriptive use vs. mildly pejorative use depending on context).