A "gwearth" is a person who is extremely confident about their passion for and knowledge of niche interests.
Differs from "geek":
A Gwearth is different than a “Geek” because "geek" only applies to pop culture genres like films and comic books. Gwearths can be militantly geeky about any category of interest like mechanics, sewing, or bird watching, and gwearths turn the tables and make fun of more balanced individuals.
A “Gwearth” also differs from a “geek” in that “gwearths” do not know that they are geeky. They are completely unaware that their obsessive interests reveal them to be comedic characters in society. Geeks, on the other hand, know what they are, and they know that they are made fun of.
Last night I met a crowd of bowling "GWEARTHS" at a party. They actually made fun of me because I did not know the terminology for bowling consecutive strikes. By the end of the party the bowling "GWEARTHS" had angrily schooled me in proper bowling lingo and etiquette. I felt demeaned and belittled by these people.