[Swordmaker]

Muumuu is not an English word.

Actually, it is. English is a language that just doesn’t borrow words from other languages, when English encounters a new language, it brow bears, mugs, and steals that languages’ words, files the serial numbers off, and incorporates its unique words into the Mulligan Stew that is the English tongue.

[Savage Beast]

Right you are, Swordy:

Oxford Dictionary of English

muumuu |ˈmuːmuː| noun
a woman's loose, brightly coloured dress, especially one traditionally worn in Hawaii.
ORIGIN early 20th century: from Hawaiian mu'u mu'u, literally ‘cut off’.

And not only is the language such a stew, but the entire culture and population are also. And here we are: all in a stew (pun intended)!

And not only the English, but everyone all over the world, whether they know it or not. The English are just more obvious--or maybe transparent is a better word--or maybe even congenial--than the rest.