I.B.

Kids with giant ass backpacks that usually go out 3 times their body's width.Usually resulting in back problems in the future.

That bag is frikin' huge. It's really I.B.

by Gojitte March 26, 2007

I.B.

A substitution of the first two letters of "irritable bowel" as the initials of someone who always has to take a shit at the worst time

I.B. Clarkson (Irritable Bowel Clarkson) could not hold it until the next exit, so he had to take a shit in the woods.

by scroty G October 6, 2009

I.B.

INSTANT BONER- refers to a female that can make a mans man stand to attention..

As soon as Alika walked in the room i knew she was an I.B.

by j*rocktrixxxkilla May 21, 2008

I.B.

Abbreviation for in bed. Usually safe to use when within earshot of parents, teachers, or anyone else who may disapprove if they heard the actual joke.

Student 1: "All this work is killing me!"
Student 2: (notices teacher nearby) "I.B."

by whohastoknow January 24, 2011

Dr. I.B. Shitting

The investor of inflammatory Bow Disease, commonly known as IBS.

Dr. I.B. Shitting was the first to move diarrhea from the bowels of the bathroom to acceptable dinner table chat with one simple acronym.

by tirtle February 9, 2019