Source : Webster's Revised Unabridged Dictionary (1913)

Bitter \Bit"ter\, a. [AS. biter; akin to Goth. baitrs, Icel.
   bitr, Dan., Sw., D., & G. bitter, OS. bittar, fr. root of E.
   bite. See {Bite}, v. t.]
   1. Having a peculiar, acrid, biting taste, like that of
      wormwood or an infusion of hops; as, a bitter medicine;
      bitter as aloes.

   2. Causing pain or smart; piercing; painful; sharp; severe;
      as, a bitter cold day.

   3. Causing, or fitted to cause, pain or distress to the mind;
      calamitous; poignant.

            It is an evil thing and bitter, that thou hast
            forsaken the Lord thy God.            --Jer. ii. 19.

   4. Characterized by sharpness, severity, or cruelty; harsh;
      stern; virulent; as, bitter reproach.

            Husbands, love your wives, and be not bitter against
            them.                                 --Col. iii.
                                                  19.

   5. Mournful; sad; distressing; painful; pitiable.

            The Egyptians . . . made their lives bitter with
            hard bondage.                         --Ex. i. 14.

   {Bitter apple}, {Bitter cucumber}, {Bitter gourd}. (Bot.) See
      {Colocynth}.

   {Bitter cress} (Bot.), a plant of the genus {Cardamine}, esp.
      {C. amara}.

   {Bitter earth} (Min.), tale earth; calcined magnesia.

   {Bitter principles} (Chem.), a class of substances, extracted
      from vegetable products, having strong bitter taste but
      with no sharply defined chemical characteristics.

   {Bitter salt}, Epsom salts; magnesium sulphate.

   {Bitter vetch} (Bot.), a name given to two European
      leguminous herbs, {Vicia Orobus} and {Ervum Ervilia}.

   {To the bitter end}, to the last extremity, however
      calamitous.

   Syn: Acrid; sharp; harsh; pungent; stinging; cutting; severe;
        acrimonious.

Source : WordNet®

Vicia orobus
     n : European perennial toxic vetch [syn: {bitter betch}]