Source : Webster's Revised Unabridged Dictionary (1913)

Anguish \An"guish\, n. [OE. anguishe, anguise, angoise, F.
   angoisse, fr. L. angustia narrowness, difficulty, distress,
   fr. angustus narrow, difficult, fr. angere to press together.
   See {Anger}.]
   Extreme pain, either of body or mind; excruciating distress.

         But they hearkened not unto Moses for anguish of
         spirit, and for cruel bondage.           --Ex. vi. 9.

         Anguish as of her that bringeth forth her first child.
                                                  --Jer. iv. 31.

   Note: Rarely used in the plural: 

               Ye miserable people, you must go to God in
               anguishes, and make your prayer to him.
                                                  --Latimer.

   Syn: Agony; pang; torture; torment. See {Agony}.

Anguish \An"guish\, v. t. [Cf. F. angoisser, fr. L. angustiare.]
   To distress with extreme pain or grief. [R.] --Temple.

Source : WordNet®

anguish
     n 1: extreme mental distress [syn: {torment}, {torture}]
     2: extreme distress of body or mind
     v 1: suffer great pains or distress
     2: cause emotional anguish or make miserable; "It pains me to
        see my children not being taught well in school" [syn: {pain},
         {hurt}]