'unambitious' originates from the prefix 'un-' meaning 'not' and the word 'ambitious', which comes from Latin 'ambitiosus', meaning 'eager for favor'.

'ambitiosus' transformed into the Old French word 'ambitieux', and eventually became the modern English word 'ambitious'. The prefix 'un-' was added to form 'unambitious'.

Initially, 'ambitious' meant 'eager for favor', but over time it evolved to mean 'having a strong desire for success'. 'Unambitious' negates this meaning.