also: じょうにん
noun
Refers to a romantic partner, often with a nuance of an extramarital or secret lover. Can be used for both male and female partners, but mistress is a common translation when referring to a woman. Somewhat literary or old-fashioned; in modern casual speech, 恋人 (こいびと) is more common.
彼には妻子がいるのに、情人がいるらしい。
He has a wife and children, but apparently he also has a mistress.
彼女は若い頃、ある画家の情人だっ
When she was young, she was the lover of a certain painter.
Composed of 情 (じょう, 'feelings, emotions') and 人 (じん, 'person'). The exact historical derivation is uncertain, but the combination naturally yields the meaning 'person of affection' or 'lover'.