Source : Webster's Revised Unabridged Dictionary (1913)

Heady \Head"y\, a. [From {Head}.]
   1. Willful; rash; precipitate; hurried on by will or passion;
      ungovernable.

            All the talent required is to be hot, to be heady,
            -- to be violent on one side or the other. --Sir W.
                                                  Temple.

   2. Apt to affect the head; intoxicating; strong.

            The liquor is too heady.              --Dryden.

   3. Violent; impetuous. ``A heady currance.'' --Shak.

Source : WordNet®

heady
     adj : extremely exciting as if by alcohol or a narcotic [syn: {intoxicating}]
     [also: {headiest}, {headier}]