gnarled · adjective, verb1
First attested Shakespeare 1603: : Thy sharpe and sulpherous bolt Splits the vn-wedgable [unwedgable] and gnarled Oke [oak]. : Measure for Measure, Act II, scene ii, line 116 Variant of knurled, from knurl. By surface analysis, gnarl + -ed, though gnarl is a later back-formation. Popular use by 19th century.
gnarled · verb2
See gnarl (Etymology 2).
Etymology from Wiktionary, CC BY-SA 4.0.