Step sib

the friend who isn’t a brother or a sister but a step brother or sister (you don’t fuck your siblings but you’ll fuck a step sibling)

*Also called a Step Mom(my) or Dad(day)

You’re my favorite Step Sibling !

by Wreck Ralph October 6, 2017

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!

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.

by Robert Seigel March 31, 2009

SIB

Self Injurious Behavior

That person just had a SIB when he punched himself.

by angel71186 February 18, 2009

sib

standard issue blonde

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

by ChrisArmstrong September 15, 2005

sib

to "suck it back" while smoking a j, l, or any type of smoking device. If one does not sib, they are wasting the substance that is being smoked

we finna sib this blunt like its the last fuckin blunt on earth.

by dasibber November 20, 2009

sib

Acronym for Still In Box
Often used in regards to makeup buying/selling.

This lip gloss is SIB.

by Melodiee April 8, 2008