sidepiece

American  

[sahyd-pees] / ˈsaɪdˌpis /

Or side piece

noun

1. a piece forming a side of something, or attached at the side.

2.  side chick.  Slang. a woman who has a continuing sexual relationship with a man who has a wife or regular girlfriend.

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Etymology

Origin of sidepiece

First recorded in 1795–1805; side ¹ + piece

Example Sentences

"Gosling submerges wholeheartedly into Ken's insecure psyche as he moves from Barbie's sidepiece to patriarchal poster boy. Every muscle flex, every hair flick, every guitar strum lands perfectly. There are moments where he will rob you of breath."

From BBC

The sidepiece of my eyeglasses broke off six months ago; I reattached it with an electrical wire I had stripped of insulation and re-employed as a hinge pin.

From Washington Post

And he’s not just being polite; he immediately mentions a song he has been working on, called Sidepiece, and then he gets very excited.

From The Guardian

“I sent you a text, you didn’t reply/ Got the two ticks, what am I?/ SIDEPIECE!”

From The Guardian

Q. Allowed to be bitter: I moved across country to be with my cheating boyfriend, and his sidepiece made it her mission to be my newest, dearest friend for close to two years.

From Slate