gnarly
adjective
[ ˈnɑːli ]
• gnarled.
• "twisted trees and gnarly roots"
• difficult, dangerous, or challenging.
• "he'd taken a fall during a particularly gnarly practice session"
Origin:
mid 19th century: from gnarl + -y1. gnarly (sense 2) was originally surfers' slang, perhaps from the appearance of rough sea.
