To vomit profusely or to make yourself vomit. A direct referance to Mary-Kate Olsen's eating disorder.
"That chinese food got the best of me. I might have to go mary-kate that shit up, here in a minute."
by Amy Christ April 29, 2005
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1) an eating-disorder-ridden, indecisive, eager-to-please perfectionist
2) a sweet, unassuming virgin who is most likely quiet and timid, speaking more with noises (hm, oh, mm) and sound bites (fun, sounds good, whatever you want to do) than actual words, often accompanied by excessive eye-lash batting and pursing of lips. see mary with a twist
3. prude, but with sooo much potential i.e. perfection
1) man you couldn’t decide on what food to order and now you're not eating it.... you going mary kate on me?

2a) i dated some britneys but I'm marrying a mary kate
2b) good luck they are a dying breed....

3a) man, all the girls at this party are whores… wait a second, who’s that hottie?
3b) that’s mary kate. she’s gorgeous, but she’s waiting til marriage.
3a) damn.
by mcluvin8485 March 19, 2009
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to force one's self to puke as in fashion with the olsen twin
i had so much pizza i had to pull a mary-kate, no dumbass i didn't take it up the ass, i puked.
by the February 16, 2005
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a girl i am in love with even though i'm a straight girl.

mary-kate olsen is the prettiest girl alive.
"that girl is a mary-kate"
by Lindsay March 24, 2005
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While I was sitting on my couch, I ate a 3 day-old moldy hot dog and immediately mary-kated all over the coffee table.
by Justin Koehler February 16, 2005
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we love you mk! wanna do some lines later?
by jjwinaba March 31, 2005
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