knotty

adjective4

1. •
   Of string or something stringlike: full of, or tied up, in knots.

   • Their heads are long, their haire curld, and seeming rather wooll, then haire; tis blacke and knotty: […] — 1634
2. •
   (figurative) Complicated or tricky; complex, difficult.

   • crop-headed, short-haired — 2017
3. •
   Of a part of the body, a tree, etc.: full of knots (knobs or swellings); gnarled, knobbly.

   • If thou murmur'st, I vvwill rend an Oake / And peg thee in his knotty entrailes, till / Thou hast hovvl'd avvay tvvelve vvinters. — 1610
4. •
   (figurative) Of an austere or hard nature; rugged.