Describes the unfortunate transition by many women from eighteen-year old nubiles into ugly, sweaty, fat, pram-faced mingers with bingo wings. If it's going to happen it usually does by the age of 35. However, it can happen straight out of adolescence, particularly for townies (British trailer trash equivalent).
Mingermorphosis is often the result of watching daytime television, a sedentry life-style and marriage. It is widely believed a pre-requisite for entrance into the audience of Trisha, Jerry Springer, and similar waste-of-space chat show programmes.
Mingermorphosis can be a by-station on the way to becoming an oxygen thief.
"Kirsty Alley used to be really hot before her mingermorphosis"