Sib 

Short for sibling. Brother or sister, mostly for borthers.

Yo, Sib. Mom just said I'm her favorite

Sib by daVirgo June 23, 2005

Sib 

Your biological sibling. Brother, Sister, or other.

"Your painting of elvis in a dress looks fantastic, sib."

Sib by LuridHope May 25, 2021

sib 

short for Suck It Bitch

bob: joe you're an idiot
joe: SIB

sib by mTk July 24, 2004

SIB 

Short for "stuck-in-between". An acronym for a group of mature and attractive women who are younger than than the usual age limit for a MILF, yet old enough for proper recognition.

Typical age range for a SIB is between 25 and 29, but there have been reported SIB sightings in women as old as 32.

My friends and I decided to hit up this cougar bar looking for some older women, but instead the bar was filled with SIB's.

Dude, did you just see how hot that SIB was, she was perfect!

SIB Conversation (Actual):
Young Man: Hey girls, how old are you?

Attractive Busty Woman and friend: Ummm...26?

YM: Wow that's perfect, you guys are just what we were looking for, SIBs!

SIB by JM & VP November 23, 2010

sib 

Acronym for "sweaty itchy butt" usually caused by inadequate wiping after a B.M., or lack of shower after defecating.

My buttcheeks are sticking together due to this horrible case of sib.

sib by Robert Seigel March 31, 2009

SIB 

Self Injurious Behavior

That person just had a SIB when he punched himself.

SIB by angel71186 February 18, 2009

sib 

standard issue blonde

Driving around Brea, you would see plenty of sib's in their SUV's

sib by ChrisArmstrong September 15, 2005