In Japanese, manba マンバ means a type of gyaru ギャル fashion style characterized by artificial dark skin color, called ganguro ガングロ, white eye-shadow, lip gloss, and colored hair.
It comes from yamanba ヤマンバ, which is a different, but similar fashion style. The difference between manba マンバ and yamanba ヤマンバ is that the original yamanba featured white hair and white makeup, while the derived manba features colored hair and makeup.
Nowadays, the two terms are often used interchangeably, mostly because this specific style of fashion was popular after the 90's and started dying out around 2000. There's a lot of misinformation on the origin of the words, nobody really remembers, and, honestly, not very many people care.
To clarify: first, some gyaru started getting dark skin, ganguro. This made them stand out in the crowd, in a country where mostly everybody had white skin. Nowadays those are called "black gyaru," kuro-gyaru 黒ギャル, and there are kinds of gyaru without ganguro.
Anyway, in order to stand out even outer, some gyaru started using makeup mimicking a certain legend: of the monster spirit yamanba, also called yamauba 山姥, which took the form of an "old woman," babaa ババァ, and lived in a "mountain," yama 山.
Since the yamanba style is supposed to mimic yamauba, we can be certain that it features white hair. After all, yamauba took the form of an old woman, and, with advanced age, women end up having white hair.
By contrast, manba, which came after, simply takes the yamanba style and removes the requirement of resembling a spirit legend, which is why it has colored hair instead of white. Sumber https://japanese-with-anime.blogspot.com/
