Byzantine, convoluted, intricate, involved, knotty, labyrinthine, tangled, tortuous

highly involved or intricate; "the Byzantine tax structure"; "convoluted legal language"; "convoluted reasoning"; "intricate needlework"; "an intricate labyrinth of refined phraseology"; "the plot was too involved"; "a knotty problem"; "got his way by labyrinthine maneuvering"; "Oh, what a tangled web we weave"- Sir Walter Scott; "tortuous legal procedures"; "tortuous negotiations lasting for months"

• complex — complicated in structure; consisting of interconnected parts