That's basically a "nickname" for people that are fourteen (fjorten) years old. It's negatively loaded. You could for instance say that trance music is very "fjortis". Sinizterguy explained it quite good too Other cool norwegian expressions are: Råner: A guy that cruises in his (lowered) car with 10000 watts of bass (and no tweeters) up and down the same strip over and over. Harry: I guess you could translate it with "tacky". A råner is usually harry as well... If you have a pink and turquoise training suit, that is harry, and so on. Grilldress: Translated it means "barbeque suit", and is usualy sort of a training suit in bright colors. Usually worn by 50 year old men at trailer parks. Owning a grilldress is quite harry.