In British slang, anorak has come to mean "geek" or "nerd", for example from the use of anoraks as the invariable wear of train spotters, and then by extension to refer to anyone with an unfathomable interest in detailed information regarded as boring by the rest of the population - aided by the intuition that only a geek would wear something so terminally unfashionable.

The word can be qualified by the area in which the person takes an (implied) excessive interest; for example in education, a "timetabling anorak" would be someone who found the process of timetabling classes fascinating.

It was reportedly derived from the weatherproof upper clothing worn by enthusiasts of offshore radio who would, despite their lack of familiarity with maritime life, sometimes travel from British ports in small boats to visit the ships from which their outcast heroes broadcast during the 1967-76 period. The collective impression of their brightly coloured garments in the coastal murk of the North Sea was presumably memorable to the crews of those "pirate ships" who had restricted contact with the mainland due to the Marine Broadcasting Offences Act and the visits might have had an important morale-boosting role, although the wearers of the garments might often have regretted the discomfort of those sea-tossed journeys. In rough weather presumably the anoraks were far more apparent than their distressed wearers so those people were identified just by the name of their outer garments. The term was reportedly coined by Andy Archer, a disc jockey who gained fame in the period following the passing of that Act by the government of Harold Wilson. The usage then become generalised to mean obsessive enthusiasts of any outdoor activity, and later to cover enthusiasts of other unfashionable activities too.

See also: Anorankh