I.M. 

its short for instant message.

do u have AIM (aol instant messenger) if u do why not I.M. me

I.M. by Bug March 9, 2004

I.M 

it Simply means imOut.!
As in Peace Out or Goodbye

Yeah iHad ahGood time.. TTYL.. I.M

I.M by OCQ.Syditty August 6, 2009

i m 

Short for "immature." To be used when you don't want to say the word "immature" because saying the word itself when refering to someone is in itself immature.

Am I going out with that girl from the bar again tonight? Hell no son, she was way i m. Only like 21 or some shit.

i m by Chris B dot April 20, 2007

i.m 

Shortened version of saying "I mean"

"Yeah i.m she's not that bad looking ig"

i.m by Take some chill pills August 14, 2017

I'm 

A way of insulting an idiot, by sarcastically claiming to be them. Simply say "I'm.." and then say their name.

Jacob: *farts on a cute girl*
Tony: I'm jacob.

I'm by thegreat_1 December 4, 2010

I.M 

Is a cute, awkward and funny korean guy that will steal your heart once you hear his voice rapping. He looks serious but is as weird and crazy as the rest of the members of the group. He's the younger one but looks and acts as if he was older. Deeper and sexy voice. Cute aegyo. Apple booty. (Changkyun, Daniel)

1: Have you heard Monsta X?
2: Yeah! I like that deep voice of the rapper
1: oh, that's I.M

I.M by Monbebe_Wonhogirl_Elf April 27, 2017

i'm- 

It's used when you don't know what to say or when you're speechless/indignant.

person 1: he said he hates you
person 2: i'm-

i'm- by kindlycrazy March 1, 2019