Occasionally used as a euphemism for the vulgar insult "motherfucker." Taken from the name of a character in the nursery rhyme "Old Mother Hubbard."

Note that one only calls a person a "mother hubbard;" the term is not used to replace other uses, as when one sees something shocking and remarks, "motherfucker."

A Mother Hubbard is a loose-fitting dress.

It was introduced to many indigenous peoples, from the Americas to the Pacific Islands and to Africa, by Christian missionaries. The style is a lot like a large loose nightgown; it is simple to sew. Its main purpose was to keep the women from showing any of their body.

The Hawaiian mumu is pretty much a Mother Hubbard style dress.