Example : A baffling problem.
I faced the knotty problem of what to have for breakfast.
A problematic situation at home.

Synonyms : baffling, elusive, problematic, problematical, tough

Example : Gnarled and knotted hands.
A knobbed stick.

Synonyms : gnarled, gnarly, knobbed, knotted

Example : The Byzantine tax structure.
Byzantine methods for holding on to his chairmanship.
Convoluted legal language.
Convoluted reasoning.
The plot was too involved.
A knotty problem.
Got his way by labyrinthine maneuvering.
Oh, what a tangled web we weave.
Tortuous legal procedures.
Tortuous negotiations lasting for months.

Synonyms : byzantine, convoluted, involved, tangled, tortuous

Example : A mass of knotted string.
Snarled thread.

Synonyms : snarled, snarly