The Collaborative International Dictionary
Knurly
Knurly \Knurl"y\ (n[^u]rl"[y^]), [Compar. Knurlier (n[^u]rl"[i^]*[~e]r); superl. Knurliest.] [See Knur, and cf. Gnarly.] Full of knots; hard; tough; hence, capable of enduring or resisting much.
Wiktionary
knurly
a. gnarled or knotty. Hard and misshapen