Gnarl may refer to: A rough, knotty protuberance, especially on a tree: Gall, any abnormal outgrowth of plant tissues, Burl, hard rounded outgrowth on a tree trunk. GNARL or Gnu Ada Runtime Library, a library for the Ada programming language Gnarl (Alien Racers), a character in the 2005 animated program Alien Racers Gnarl, a character in the 2007 video game Overlord Gnarl!, a 2000 short story collection by Rudy Rucker See also Knurl (band), a noise music project of Alan Bloor