a girl in a group of other girls that is drastically uglier and broader than the rest often making them look better(may also be a cockblock). the term is derrived from the phrase "Designated ugly fat friend". The -y at the end is added so the word can be used freely in the presence of the duffy without making it obvious that you are making fun of her.
Yo those girls over there are pretty hot...aw man dude, they got a duffy. I call she's not mine.
by Fil P August 24, 2007
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duffy is a term in which to call a semi mildly mental retarded person

duffy is also a mistake or big accident
by righteousreviewz September 14, 2019
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one of the funniest guys around, lives in sydney and roams around the northshore.
"what the hell some guy over there is running around naked"

"dont worry bro, its just duffy hahaha"
by banana fingers September 8, 2004
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a person who when telling a story, never gets to the point and when he/she finally does, all audience has lost interest, fallen asleep, or killed themselves.
Let me tell you another story about my tales in the south
oh god, looks like we got a duffy
somebody plan my funeral
by Bode H February 12, 2008
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When your spelling is so bad your own mother cannot read it and rejects you as one of her offspring.
Dude I have no clue what you wrote you really pulled a Duffy in that text.
by Kicksumass January 4, 2022
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In the act of sex, when the male is ready to ejaculate, he pulls out and inserts the tip of his penis into the nostril of the sex partner. And ejaculates inside of the nasal cavity. Ending result is sperm dripping down the throat of the sex partner.
Judy: Hey Amber why does your nose look all red?

Amber: Oh he Duffy'd me last night again.
by jewbone25 August 16, 2011
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to premature ejactulate; to ruin one's reputation by releasing skeet all over a girl
He blew his chance when he blew his load too early, his duffy was his own cockblock.
by SamFlash February 23, 2006
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