Learn the lmao meaning and discover how to use this popular internet slang as well as other slang terms. Find out what lmao means and its origin, along with examples and usage tips. LMAO (Internet slang, text messaging, mildly vulgar) Initialism of laughing my ass/arse off; used to indicate great amusement, usually exaggerated. quotations LMAO is an abbreviation for laughing my ass off, used to express amusement or humor online or in text messages. Learn more about its usage, origin and translations in different languages. What does LMAO mean? Learn the meaning of popular Internet acronyms and slang terms, such as LMAO , ROF, BRB, and more!