knotty

adj

1.
making great mental demands; hard to comprehend or solve or believe
baffling elusive problematic problematical tough
Derived from:
knottiness
2.
used of old persons or old trees; covered with knobs or knots
gnarled gnarly knobbed knotted
3.
highly complex or intricate and occasionally devious
Byzantine convoluted involved labyrinthine tangled tortuous
Derived from:
knottiness
4.
tangled in knots or snarls
snarled snarly
Derived from:
knot