mwahahaha Syllabification: (mwa·ha·ha·ha)Pronunciation: /ˈmwähähähä/ (also muahahaha, bahahaha)Definition of mwahahaha exclamation informal used to represent laughter, especially triumphal or cackling laughter such as that uttered by a villainous character in a cartoon or comic strip:World domination, at last, is at hand. Mwahahaha!Origin: 1980s: imitative, on the pattern of ha hamwahahaha in other Oxford dictionaries Definition of mwahahaha in the British & World English dictionary