Mr Brightside or a Brightside is someone who is jealous of another person who is with the person they want. This is taken from The Killers' song Mr Brightside.
"And I'm falling asleep, and shes calling a cab, while he's having a smoke, and she's takin' a drag, now they're goin' to bed, and my stomach is sick, and its all in my head but she's touching his ... chest now, he takes off her dress, now LET ME GO"

"Jealousy, turning saints into the sea, swimming through sick lullabies, choking on your alibi, but its just the price I pay, destiny is calling me, open up my eager eyes, cause I'm Mr Brightside"

by Craig McCombie October 29, 2006
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A guy who has terrible luck with with girls, or anyone who catches a lot of tough breaks in general.
- 'But it's just the price I pay, Destiny is calling me, Open up my eager eyes, Cause I'm Mr. Brightside'

- "wow the girl u like just started going out with another guy... better luck next time mr. brightside."

by ajaku3714 February 24, 2008
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Someone who knows his girlfriend is cheating on him, or at least messing around with a bunch of other guys, but chooses to ignore it because he can't resist her.

Made popular by The Killers's song, "Mr. Brightside."
"Dude, Jeffery's girl is over there making out with some guy! Does he know about it?"

"Yeah, but he's a Mr. Brightside, so he just ignores it."
by Allison Silsbee November 8, 2009
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A song that posseses the spirit of the white man. They worship this song whenever it comes on in a club or at pre drinks. They seem to believe that it is the best song in the universe and sing every single word at the top of their lungs whilst bouncing up and down. This song can also be accompanied by come on Eileen
*intro to mr brightside begins to play*
by Geeked132 December 4, 2017
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The condition where one likes or knows only the most popular song from a band or artist.
"Hey, what's your favorite song by My Chemical Romance?"
"Defiantly Welcome to the Black Parade"
"Yo you totally got Mr. Brightside Syndrome"
by gingecan July 2, 2014
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A Mr. Brightside moment is a moment of instant heart-break. You can hear the intro of Mr. Brightside in your head.
This girl broke his heart and he just stared at the wall. A certified Mr. Brightside moment.
by wordfrog May 14, 2020
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I didn't want to have sex with him, so I just gave him a Mr. Brightside.
by J3L August 25, 2008
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