gnarly
Concise Oxford English Dictionary © 2008 Oxford University Press:
gnarly/ˈnɑːli/
▶adjective (gnarlier, gnarliest)
- 1 gnarled.
- 2 N. Amer. informal dangerous or difficult. [orig. surfers' slang, perh. from the appearance of rough sea.]
■ unpleasant or unattractive.
- 3 N. Amer. informal excellent.
'gnarly' also found in these Oxford entries:

