1. 
[syn: gnarled, gnarly, knotted, knotty, knobbed]
The Collaborative International Dictionary of English v.0.48:
Gnarly \Gnarl"y\, a.
   Full of knots; knotty; twisted; crossgrained.
   [1913 Webster]
WordNet (r) 3.0 (2006):
gnarly
    adj 1: used of old persons or old trees; covered with knobs or
           knots; "gnarled and knotted hands"; "a knobbed stick"
           [syn: gnarled, gnarly, knotted, knotty,
           knobbed]
The Jargon File (version 4.4.7, 29 Dec 2003):
gnarly
 /nar'lee/, adj.
    Both obscure and hairy (sense 1). ?Yow! ? the tuned assembler
    implementation of BitBlt is really gnarly!? From a similar but less
    specific usage in surfer slang.
The Free On-line Dictionary of Computing (30 December 2018):
gnarly
    /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)