'unintellectual' originates from the prefix 'un-' meaning 'not' and the word 'intellectual', which comes from Latin 'intellectus', meaning 'understanding'.

'Intellectus' transformed into the Old French word 'intellectuel', and eventually became the modern English word 'intellectual'.

Initially, it meant 'pertaining to understanding', but over time it evolved into its current meaning of 'lacking intellectual qualities'.