adjective, knot·ti·er, knot·ti·est.
- having knots; full of knots: a knotty piece of wood.
- involved, intricate, or difficult: a knotty problem.
adjective -tier or -tiest
- (of wood, rope, etc) full of or characterized by knots
- extremely difficult or intricate
mid-13c. (figurative use early 13c.), from knot (n.) + -y (2). Related: Knottiness.