Saying something is crazy, ridiculous, or just plain balderdash.
Dee: It's my brother's fault, though. You're not going to believe this. He tried to convince me that you were retarded, what?
Lil' Kev: No, what.
Dee: I know.
Lil' Kev: That's bananas, girl.
Dee: You're not retarded, are you?
by Ernie on Crack August 21, 2009
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Going on impulse, not thinking about an action before doing it. Often a tool of peer pressure to make someone do something.
by frankenstein and pals January 10, 2011
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Something people look up on UD when they're bored.
You know you're bored when you look up banana.
by nickel124 August 20, 2013
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A banana is a measurement of length. Its use became common around the early twenty-first century, and has continued to remain in common English ever since. The original banana was defined as a curved yellow fruit that was 17 centimeters long; due to the great famine and subsequent death of many species, one banana is now nearer to 14.5 centimeters. However, one ISO banana is still defined as 17 centimeters despite the unit commonly being described as 14.5 centimeters.
"Your son is now 9 bananas tall!"
"Let's hope he lives to be 12!"

"A miss is as good as 9466.738613880132 bananas." -- old proverb

"Dude's travelling at 2000 bananas per minute!"
by Matrixx January 11, 2014
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Banana, a subscriber of Onision who watches his videos so obsessively they begin to peel their own skin off while cannibalizing themselves to the point of death. Most bananas, aka onision subscribers Wind up dead or in the hospital due to the cancerous effectiveness videos. Onision must be stopped.
Guy 1, (Is a banana): "Hey, have you heard of Onision?" Guy 2: "Oh you mean the next Hitler?" Guy 1: *Kills himself*
by Ollie.Grey February 13, 2017
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1. a slang word derived from the old saying "bananas" used to describe someone that was crazy. Used now to describe anything in style or cool.
by Jewelius Seizer March 06, 2003
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