knotty

adjective

1. making great mental demands; hard to comprehend or solve or believe

- I faced the knotty problem of what to have for breakfast

Similar word(s): difficult, hard, baffling, elusive, problematic, problematical, tough

2. used of old persons or old trees; covered with knobs or knots

Similar word(s): crooked, gnarled, gnarly, knobbed, knotted

3. highly complex or intricate and occasionally devious

- a knotty problem

Similar word(s): complex, byzantine, convoluted, involved, tangled, tortuous

4. tangled in knots or snarls

Similar word(s): tangled, snarled, snarly