Illicit partner of a married man or woman

Illicit partner of a married man or woman is called?

Answer: Paramour

Paramour – A lover or a romantic partner, especially the illicit partner of a married person is known as Paramour.

Polyandry – The practice or condition of having more than one husband at the same time.

Polygamy – The act of marrying multiple spouses, that means having more than one husband or wife at the same time.

Polyglot – A person who knows and is able to use several languages.