gnarled adjective

1. Knotty
2. Contorted
3. Rugged, weather-beaten

gnarlˈy adjective (gnarlˈier; gnarlˈiest)

1. Gnarled
2. Ill-natured, bad-tempered
3. Difficult, challenging (informal)

knurl or nurl /nûrl/

1. A small excrescence or protuberance
2. A ridge or bead, esp in series, eg in the milling of a screw-head
3. A dwarfish person (Burns)

To make knurls on, to mill

knurled adjective (spelt gnarled in Shakespeare, Measure for Measure II.2)

Covered with knurls

knurlˈing noun

Mouldings or other woodwork elaborated into a series of knobs

knurlˈy adjective

Gnarled