anorak:  This was originally a word in the Inuit language of Greenland: annoraaq. It came into English in the 1920s, by way of Danish. At first it was used only to refer to the sort of garments worn by Eskimos, but by the 1930s it was being applied to a waterproof hooded coat made in imitation of these. In Britain, such jackets came to be associated with the sort of socially inept obsessives who stereotypically pursue such hobbies as train-spotting and computer-gaming, and by the early 1980s the term ‘anorak’ was being contemptuously applied to them.
Eskimo's waterproof, hooded jacket, 1924, from Greenland Eskimo anoraq. Applied to Western imitations of this garment from 1930s. In British slang, "socially inept person" (Partridge associates it with a fondness for left-wing politics and pirate radio) by 1983, on the notion that that sort of person typically wears this sort of coat.