Source : Webster's Revised Unabridged Dictionary (1913)

Mad \Mad\, a. [Compar. {Madder}; superl. {Maddest}.] [AS. gem?d,
   gem[=a]d, mad; akin to OS. gem?d foolish, OHG. gameit, Icel.
   mei?a to hurt, Goth. gam['a]ids weak, broken. ?.]
   1. Disordered in intellect; crazy; insane.

            I have heard my grandsire say full oft, Extremity of
            griefs would make men mad.            --Shak.

   2. Excited beyond self-control or the restraint of reason;
      inflamed by violent or uncontrollable desire, passion, or
      appetite; as, to be mad with terror, lust, or hatred; mad
      against political reform.

            It is the land of graven images, and they are mad
            upon their idols.                     --Jer. 1. 88.

            And being exceedingly mad against them, I persecuted
            them even unto strange cities.        --Acts xxvi.
                                                  11.

   3. Proceeding from, or indicating, madness; expressing
      distraction; prompted by infatuation, fury, or extreme
      rashness. ``Mad demeanor.'' --Milton.

            Mad wars destroy in one year the works of many years
            of peace.                             --Franklin.

            The mad promise of Cleon was fulfilled. --Jowett
                                                  (Thucyd.).

   4. Extravagant; immoderate. ``Be mad and merry.'' --Shak.
      ``Fetching mad bounds.'' --Shak.

   5. Furious with rage, terror, or disease; -- said of the
      lower animals; as, a mad bull; esp., having hydrophobia;
      rabid; as, a mad dog.

   6. Angry; out of patience; vexed; as, to get mad at a person.
      [Colloq.]

   7. Having impaired polarity; -- applied to a compass needle.
      [Colloq.]

   {Like mad}, like a mad person; in a furious manner; as, to
      run like mad. --L'Estrange.

   {To run mad}.
      (a) To become wild with excitement.
      (b) To run wildly about under the influence of
          hydrophobia; to become affected with hydrophobia.

   {To run mad after}, to pursue under the influence of
      infatuation or immoderate desire. ``The world is running
      mad after farce.'' --Dryden.

Madder \Mad"der\, n. [OE. mader, AS. m[ae]dere; akin to Icel.
   ma?ra.] (Bot.)
   A plant of the {Rubia} ({R. tinctorum}). The root is much
   used in dyeing red, and formerly was used in medicine. It is
   cultivated in France and Holland. See {Rubiaceous}.

   Note: Madder is sometimes used in forming pigments, as lakes,
         etc., which receive their names from their colors; as.
         madder yellow.

   {Field madder}, an annual European weed ({Sherardia
      arvensis}) resembling madder.

   {Indian madder}, the East Indian {Rubia cordifolia}, used in
      the East for dyeing; -- called also {munjeet}.

   {Wild madder}, {Rubia peregrina} of Europe; also the {Galium
      Mollugo}, a kind of bedstraw.

Source : WordNet®

mad
     adj 1: roused to anger; "stayed huffy a good while"- Mark Twain;
            "she gets mad when you wake her up so early"; "mad at
            his friend"; "sore over a remark" [syn: {huffy}, {sore}]
     2: affected with madness or insanity; "a man who had gone mad"
        [syn: {brainsick}, {crazy}, {demented}, {distracted}, {disturbed},
         {sick}, {unbalanced}, {unhinged}]
     3: marked by uncontrolled excitement or emotion; "a crowd of
        delirious baseball fans"; "something frantic in their
        gaiety"; "a mad whirl of pleasure" [syn: {delirious}, {excited},
         {frantic}, {unrestrained}]
     4: very foolish; "harebrained ideas"; "took insane risks behind
        the wheel"; "a completely mad scheme to build a bridge
        between two mountains" [syn: {harebrained}, {insane}]
     [also: {madding}, {madded}, {maddest}, {madder}]

madder
     n : Eurasian herb having small yellow flowers and red roots
         formerly an important source of the dye alizarin [syn: {Rubia
         tinctorum}]
     v : color a moderate to strong red

madder
     See {mad}