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A group of bro's all wearing different color polo shirts.
Brian and all his friends came over last night in different colored polo's. I could practically taste the rainbro.
by Reisencach February 08, 2010
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Aug 11 Word of the Day
A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.
"My boyfriend has a total case of brain worms. He told me the cat was bugged so the Feds could listen in on us having sex..."

or

"You totally stumbled over that entire sentence. Can't speak English all of a sudden? What, do you have brain worms?"
by _Jez_ October 03, 2009
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2
A homosexual male, who still maintains all the qualities of true bro's. The best example is Neil Patrick Harris.
Friend 1- Wait, so you're saying Esteban played basketball today? I thought he was gay.

Friend 2- He is. He's just an ultimate rainbro.
by Rainbro May 16, 2011
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3
A straight male who supports his gay friends' lifestyle.
He's not gay, he's just supportive of his friends; a true rainbro.
by test tickle February 29, 2016
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4
The gay guy in the group of straight guys.
Dude 1: Is Patrick your black friend?
Dude 2: No, he's just our rainbro.
by Danz Ferdinand January 15, 2008
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5
A Rainbow brother: Someone (male) who's been met at a Rainbow gathering and feels very close.
So where did you guys meet? => He's my rainbro!
by OneWorldDestiny December 23, 2018
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6
When two guys cum in each other's hands, then high-five, letting the cum rain on them.
Me and my boyfriend, Joey, decided to get extreme with our relationship. We jacked off together, catching each other's cum, then high-fived while listening to Metallica. We then created the Rainbro.
by Jewlz&Woody March 11, 2020
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