paramour
Paramour is a noun meaning a romantic partner, especially one who is kept secret or engaged in an illicit relationship. While it can refer to a partner of any gender, the term carries a sense of discreetness and social taboo and is most often used to describe involvement outside a marriage or other committed relationship. In modern usage it is relatively formal or literary and less common in everyday speech, where 'lover' or 'affair partner' are more typical.
Originating in Old French par amour, literally "by love" or "for love," paramour entered English in the
Paramour connotes secrecy and sometimes breach of trust. It does not imply legal status or consent beyond
Related terms include 'lover' and 'mistress' (the latter typically female and sometimes with illicit implications), as