A person practicing monogamy and or unfamiliar with polyamorous culture and practices. Usually used by the polyamorous internet community. Rather than derogatory, this is most often used as a term of endearment for friends, family and allies of polyamorous individuals.
A pear-shaped homosexual male, characterized by a large round buttocks and bulbous belly, below a thin upper body. Movement of a mangoose can best be described as waddling, while thin birdlike arms are held horizontally with hands dangling limply at the ends (similar to the arms of a Tyrannosaurus Rex).
I'd fuck a fat lady before I'd touch Puddingbutt, he's a total mangoose.