roflmfao Share definition Flag "Rolling on the floor laughing my fucking ass off" It's an internet ancronym. Mostly used on Chat Rooms or games. Play3r1: Hey man, that n00b tk'ed his team mates! Play3r2: ROFLMFAO N00b!!! roflmfao by urbandictionaryn00b June 3, 2013 Get the roflmfao mug.