Why was clemency trending last week?
1829, "knotted and rugged," from gnarl (see gnarled) + -y (2). Picked up 1970s as surfer slang to describe a dangerous wave; it had spread in teen slang by 1982, where it meant both "excellent" and "disgusting."
[1980s+ Teenagers; said to have originated among 1970s surfers, describing a dangerous wave; this sense persisted among skateboarders until at least 1988]
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)