'paramour' originates from Middle English, ultimately from the Old French phrase 'par amour,' where 'par' meant 'by' or 'for' and 'amour' meant 'love'.

'paramour' changed from the Old French phrase 'par amour' into Middle English 'paramour' and eventually became the modern English word 'paramour'.

Initially it meant 'by/for love' or referred to actions done 'for love'; over time it evolved to mean 'a lover' and increasingly carried the sense of 'an illicit lover' in later usage.