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3.
a person who is the opposite of smart
joe wilson is a dumby because he had a chance to date the hottest/nicest girl in school, but he blew it because he is a dumby
by jayfelice December 23, 2003
 
1.
Common misspelling of the word dummy, almost always used by the people who can easily be described by the word itself. Just because dumb has a "b" at the end, does not mean dummy has to. Also, dummy does not rhyme with Gumby.
"You are such a dumby!" -Lauren, Monica, etc...
"Actually, you are the dummy!" -Brandon
by Crunk Dizzle September 28, 2006
 
2.
fake ROCKs (crack cocaine)
these fools still be feindin my dumbys
by OF CORSE its alex August 28, 2003
 
4.
When someone is acting dumb, they are a dumby. The logical spelling of the popular word dummy.

Pronounced (DUM-b-EE)
Jerome: Gosh, Alan, you're being such a dumby!
Alan: What the hell, Jerome? Dumby? What is that?
Jerome: You're being dumb. You're a dumby!
by Jemima Hootensnancle October 29, 2007
 
5.
A person with no common sense. One who lacks all judgement.
The Bling is a big dumby.
by Nads August 26, 2004
 
6.
A noun used to represent dumb or slow people. Also can be used as an adjective.
"You are a serious dumby."
"Hey you dumby jerk, why are you taking my car?"
by $tefen September 01, 2006
 
7.
A verb meaning "very", the preppy version of the term dumb.
I was dumby tired during math class, so I fell asleep.
by KissTheStars December 09, 2006