A lover, especially one in an adulterous relationship.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "paramour" in a sentence
"We also heard it had been rented or owned by William Randolph Hearst for his long-term paramour, Marion Davies."
"In “Beauty and the Beast” or “The Frog Prince,” the animal paramour is an enchanted human, so by means of a deus ex machina, the beast becomes a prince."
"He talked the Luciano gang into backing him in building his dream casino, The Flamingo, the nickname he called his paramour Virginia Hill."