Modern slang, especially in extreme sports, meaning to perform aggressively or impressively, or to tackle something with intensity and skill.
Possibly from 'gnarl' (to snarl or twist) or imitative origins in skateboarding and snowboarding culture starting in the 1980s-90s California counter-culture.
Gnar entered mainstream slang through extreme sports communities and has evolved to mean handling challenges fearlessly—it's linguistic evidence of how subcultures create their own languages that eventually influence the broader culture.
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