Source : Webster's Revised Unabridged Dictionary (1913)

Knotty \Knot"ty\, a. [Compar. {Knottier}; superl. {Knottiest}.]
   1. Full of knots; knotted; having many knots; as, knotty
      timber; a knotty rope.

   2. Hard; rugged; as, a knotty head.[R.] --Rewe.

   3. Difficult; intricate; perplexed.

            A knotty point to which we now proceed --Pope.

Source : WordNet®

knotty
     adj 1: making great mental demands; hard to comprehend or solve; "a
            baffling problem"; "I faced the knotty problem of what
            to have for breakfast"; "a problematic situation at
            home" [syn: {baffling}, {problematic}, {problematical}]
     2: used of old persons or old trees; covered with knobs or
        knots; "gnarled and knotted hands"; "a knobbed stick"
        [syn: {gnarled}, {gnarly}, {knotted}, {knobbed}]
     3: 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},
         {labyrinthine}, {tangled}, {tortuous}]
     [also: {knottiest}, {knottier}]