Outside of england, this is a term used by students who have went to a new city for school to describe the natives of that town. It is often seen as derogitory by those who use it, but townies themselves often embrace it as a badge of honour.
A bastardized genre of music in which the distorted guitars and agressive vocals of hardcore and heavy metal are dumbed down musically and then packaged to be marketable to angst-ridden teens. The name is derived from the "-core" system often used to name metal and punk varients such as hardcore, metalcore and emocore, and is so named because it targets your standard mall-going teens rather than real music enthusiasts, who nearly unanimously dismiss it as garbage. It can be characterized by chugging riffs based around basic (and often no) progression, and angsty yelled or rapped vocals. The lyrical content often complains about the unfairness of teenage situation, parents, school, or in rare cases politics. There is very little place for any musical innovation, and electronic effects and samples have taken the place of guitar solos and the like in 90% of the genre's bands.
Trendy kids who believe that they are "goths" when they have no understanding of the scene. Typically have baggy jeans, black dyed hair and trendy band t-shirts. Often associate their knowledge of HIM (who are a good band nonetheless) with connection to underground, when they have no real knowledge of real gothic music. While these people are often worthless as human beings, they can often be hot, and easily persuaded to do whatever you want them to for attention, particularly if they think you are "evil". They are also fun to scare the shit out of if you have an understand of real goth/black metal culture.
I have personally scared a mallgoth into a preppy by showing them a Countess album.
In the warhammer 40k universe, a derogitory term for Humans used by the alien Eldar.
Its origins stem from a race of sub-intelligent beasts who once enslaved the eldar and were later killed, and though associated most often with humans, it broadly represents any race which the Eldar deem worthy of extermination.
"filth mon-keigh...you're people know nothing of our pain"
"the mon-keigh cannot hope to withstand the might of the craftworlds"