Source : Webster's Revised Unabridged Dictionary (1913)

Promise \Prom"ise\, a. [F. promesse, L. promissum, fr.
   promittere, promissum, to put forth, foretell, promise; pro
   forward, for + mittere to send. See {Mission}. ]
   1. In general, a declaration, written or verbal, made by one
      person to another, which binds the person who makes it to
      do, or to forbear to do, a specified act; a declaration
      which gives to the person to whom it is made a right to
      expect or to claim the performance or forbearance of a
      specified act.

            For if the inheritance be of the law, it is no more
            of promise: but God gave it to Abraham by promise.
                                                  --Gal. iii.
                                                  18.

   2. (Law) An engagement by one person to another, either in
      words or in writing, but properly not under seal, for the
      performance or nonperformance of some particular thing.
      The word promise is used to denote the mere engagement of
      a person, without regard to the consideration for it, or
      the corresponding duty of the party to whom it is made.
      --Chitty. Parsons. Burrill.

   3. That which causes hope, expectation, or assurance;
      especially, that which affords expectation of future
      distinction; as, a youth of great promise. --Shak.

            My native country was full of youthful promise. --W.
                                                  Irving.

   4. Bestowal, fulfillment, or grant of what is promised.

            He . . . commanded them that they should not depart
            from Jerusalem, but wait for the promise of the
            Father.                               --Acts i. 4.

Promise \Prom"ise\, v. t. [imp. & p. p. {Promised}; p. pr. & vb.
   n. {Promising}.]
   1. To engage to do, give, make, or to refrain from doing,
      giving, or making, or the like; to covenant; to engage;
      as, to promise a visit; to promise a cessation of
      hostilities; to promise the payment of money. ``To promise
      aid.'' --Shak.

   2. To afford reason to expect; to cause hope or assurance of;
      as, the clouds promise rain. --Milton.

   3. To make declaration of or give assurance of, as some
      benefit to be conferred; to pledge or engage to bestow;
      as, the proprietors promised large tracts of land; the
      city promised a reward.

   {Promised land}. See {Land of promise}, under {Land}.

   {To promise one's self}.
      (a) To resolve; to determine; to vow.
      (b) To be assured; to have strong confidence.

                I dare promise myself you will attest the truth
                of all I have advanced.           --Rambler.

Promise \Prom"ise\, v. i.
   1. To give assurance by a promise, or binding declaration.

   2. To afford hopes or expectation; to give ground to expect
      good; rarely, to give reason to expect evil.

            Will not the ladies be afeard of the lion? I fear
            it, I promise you.                    --Shak.

Source : WordNet®

promise
     n 1: a verbal commitment by one person to another agreeing to do
          (or not to do) something in the future
     2: grounds for feeling hopeful about the future; "there is
        little or no promise that he will recover" [syn: {hope}]

promise
     v 1: make a promise or commitment [syn: {assure}]
     2: promise to undertake or give; "I promise you my best effort"
     3: make a prediction about; tell in advance; "Call the outcome
        of an election" [syn: {predict}, {foretell}, {prognosticate},
         {call}, {forebode}, {anticipate}]
     4: give grounds for expectations; "The new results were
        promising"; "The results promised fame and glory"