The complete opposite of "mainstream." It IS a horrible play on words. It is a new way to refer to a hipster without them getting pissed off (cause hipsters hate to be called hipsters).
"I thought you were too mainstream to have a facebook"
"Na, I's sidebrook"
© 1999-2015 Urban Dictionary ®
Free Daily Email
Type your email address below to get our free Urban Word of the Day every morning!
Emails are sent from email@example.com. We'll never spam you.