An Undercover Slut is a guy or girl who seems quite innocent and maybe even a bit prude but is actually a sexual deviant when given the chance to be. Being that the person is generally quiet and reserved about said deviancy, it's quite surprising when they reveal their true colors and you often find yourself very, VERY intrigued and wanting more. Just remember that they are, in fact, undercover, and have to uphold their mild-mannered alter-ego when exposed to the general public, and you must respect that. Also, don't assume that they've hooked up with tons of people- most Undercover Sluts like to reserve their sluttiness as to keep it meaningful and, obviously, undercover.
It's sort of like when the chick in the movie takes off her glasses and pulls her hair down and straddles you and you get the idea.
Guy 1: "Hey, you know that chick Gracie?"
Guy 2: "The one who always gets like, really good grades? Yeah, what about her?"
Guy 1: "That party last night, dude... You wouldn't be able to tell, but she is a MAJOR Undercover Slut."
Guy 2: "Oh my god, really? Wow... I never would have guessed it.. That's awesome."
Guy 1: "Yeah, but don't tell anyone man."
by SwaggieG September 8, 2013
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A girl who one would not assume gets with a lot of guys (whether because she is weird, nerdy, or just really nice) but in reality has hooked-up with half the school.
Bob: That Mindy girl's pretty cute, she seems really smart though. I wonder if she'd get with you.

Joe: Dude, she's an undercover slut. She gets with everyone!
by M.C. Skizzlet September 2, 2010
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A girl/boy who appears very innocent but is a huge slut on booze/ behind closed doors
Lucy is such an undercover slut, who knew she's fucked every lad in the village
by Potatosmugler69 July 21, 2015
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A girl that's playing you and fucking all your friends at the same time.
Damn, she's a tricky undercover slut.

She thinks she's a tricky undercover slut but I'm on to her.
by Sariel October 22, 2014
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The girl that you wouldn't expect to be easy and hides her body count very well. Another word for Closeted Whore.
Ledantre: This girl _____ I've been talking to is honestly the best dude.
Sharmarquerifa: Yoooo, you ain't heard? She one of them Undercover Slut's, don't hit it dude you might catch somethin'.
by BubbaGumpsShrimpBoat February 6, 2020
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