L.M.M.F.A.O. 

Laugh my mother fucking ass off.

You would use this when talking to someone online or when writing a letter and your too lazy to writ it all out.

Val fell on her ass today, lmmfao.

L.M.M.F.A.O. by nevada December 2, 2003

L.M.G.D.M.F.A.O

Abbreviation for the term Laughing My God Damn Mother Fucking Ass Off. Often used online when one can't be bothered to actually say it all.

person1: I fell off my bike today and twisted my ankle
person2: L.M.G.D.M.F.A.O.

L.M.G.D.M.F.A.O by Deans_babi_gurl September 9, 2005

l.m.f.a.o 

Laughing My Fucking Ass Off. A term used when you are in tears from laughter. Used mostly on instant messaging.

Ben: I did the stupidest thing last nite, i was running down the street with Alex and I ran straight into a pole, i ran so hard i think i dinted it!

Kyle: U are such an idiot. l.m.f.a.o!

l.m.f.a.o by Jessie_xxx November 21, 2005

L.M.F.A.O. 

an abbreviation for saying: LAUGHING MY FUCKIN' ASS OFF

HAHAHAHA. that was very funny. L.M.F.A.O.

L.M.F.A.O. by Diego Delgadillo November 11, 2006

L.M.F.A.O.F.O.O.M.C.A.D.M.T 

Laughing my fucking ass off falling out of a chair and dropping my taco. This phase can be used while texting, or posting funny things on MLIA

Emily: *says joke*
Lauren: L.M.F.A.O.F.O.O.M.C.A.D.M.T HAHAHAHHA
Emily: hahaha, oh no your taco!

L.M.F.A.O.F.O.O.M.C.A.D.M.T by Ke$ha girl 123 November 10, 2010

L.M.F.A.O.W.R.O.F.L.O.L 

Laughing My Fuckin Ass Off While Rolling On Floor Laughing Out Loud

guy 1: did you see that n00b get pwnd
guy 2: yeah i was L.M.F.A.O.W.R.O.F.L.O.L
guy 1: you too!

L.M.F.A.O.W.R.O.F.L.O.L by Little Ninja April 4, 2009

R.O.T.F.L.M.F.B.A.O.L.O.L

Rolling

On
The
Floor
Laughing
My
Fat
Black
Ass
Off
Laughing

Out
Loud

Guy #1:Holy shit. That guy got pimp smacked by a he-bitch
Guy #2:R.O.T.F.L.M.F.B.A.O.L.O.L

Guy #1:Wow, just say lol for once

R.O.T.F.L.M.F.B.A.O.L.O.L by kittycatsid November 4, 2009