"Mumu" is not a very common word in English language, but it is sometimes used to refer to a loose, shapeless garment or a house dress. Its synonyms include a number of more common words such as nightgown, caftan, kaftan, robe, tunic, shift, and sack dress. Other alternatives to "mumu" might include a maxi dress, sundress, or beach cover-up. The term is often associated with relaxed, casual attire and can be worn for comfort or simply to stay cool in warm weather. Whatever your personal style may be, there are plenty of words to describe the loose, comfortable garments that fall under the umbrella of a "mumu".