1829, from gnarl (see gnarled) + -y (2). Picked up 1970s as surfer slang to describe a dangerous wave; it had spread in teen slang by 1980s, where it meant both "excellent" and "disgusting."
mod. extreme; excellent; great; superior. (California.) : This pizza is too gnarly for words!
Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition. Copyright 2007. Published by McGraw Hill.
Cite This Source
FOLDOC
Computing Dictionary
gnarly definition
jargon /nar'lee/ Both obscure and hairy. "Yow! - the tuned assembler implementation of BitBlt is really gnarly!" From a similar but less specific usage in surfer slang. [Jargon File] (1996-09-17)