Source : Webster's Revised Unabridged Dictionary (1913)

Tortuous \Tor"tu*ous\, a. [OE. tortuos, L. tortuosus, fr. tortus
   a twisting, winding, fr. torquere, tortum, to twist: cf. F.
   tortueux. See Torture.]
   1. Bent in different directions; wreathed; twisted; winding;
      as, a tortuous train; a tortuous train; a tortuous leaf or
      corolla.

            The badger made his dark and tortuous hole on the
            side of every hill where the copsewood grew thick.
                                                  --Macaulay.

   2. Fig.: Deviating from rectitude; indirect; erroneous;
      deceitful.

            That course became somewhat lesstortuous, when the
            battle of the Boyne had cowed the spirit of the
            Jakobites.                            --Macaulay.

   3. Injurious: tortious. [Obs.]

   4. (Astrol.) Oblique; -- applied to the six signs of the
      zodiac (from Capricorn to Gemini) which ascend most
      rapidly and obliquely. [Obs.] --Skeat.

            Infortunate ascendent tortuous.       --Chaucer.
      --{Tor"tu*ous*ly}, adv. -- {Tor"tu*ous*ness}, n.

Source : WordNet®

tortuous
     adj 1: 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" [syn: {Byzantine}, {convoluted},
             {intricate}, {involved}, {knotty}, {labyrinthine}, {tangled}]
     2: marked by repeated turns and bends; "a tortuous road up the
        mountain"; "winding roads are full of surprises"; "had to
        steer the car down a twisty track" [syn: {twisting}, {twisty},
         {winding}]
     3: not straightforward; "his tortuous reasoning"