grinfucking - the act of being (pretending to be) really nice to someone's face and then turning around and stabbing them in the back

past tense: "grinfucked"

related: "grinfucker" - one who commits such acts
Laura told me she loved my outfit, then told Mike I dressed like a whore; I can't believe she grinfucked me like that. What a grinfucker.
by ckd December 5, 2003
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When you are "fucked", or taken advantage of, by a lie told from a grinning mouth.

The smiling used car salesman using lies, convinces a customer to buy a car that breaks down a week later. The customer was grinfucked.
by Brad Johnson June 18, 2006
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From the song, Grinfucked on The Fury of Our Maker's Hand by Devil Driver. Meaning to screw someone over all the while they believe you are their friend.
The way your boss took the credit for your work all the while telling you that he was going put you up for promotion. You just got grinfucked hard.
by Hydroeric April 10, 2006
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The act of slitting somebodies mouth open from side to side (IE chelsea smile) And then repeatedly fucking the gaping wound.
by Candyclub4kids July 24, 2011
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To fuck up someone's grin when they are grinning like no other
Joe came in grinning today so I told him I fucked his girlfriend. Joe became grinfucked.
by Peppershit Cornstalk August 14, 2009
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The act of making a "WHOO" sound really loud and its sorta like a death metal growl.
"Hey grinfuck that guy!"

-innocent guy walks by-

"WHOO!!"

-guy gets scared runs away"
by Mr.Sexy September 4, 2007
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Someone smiling in your face but pounding the backside of the real true feelings he owns … angry smiler
Paul greeted new cottage owners with a welcoming smile while exhibiting his grinfucker true thoughts of never allowing a new road passage across his property
by Ol’Murch August 22, 2021
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