Source : Webster's Revised Unabridged Dictionary (1913)

Surmise \Sur*mise"\, n. [OF. surmise accusation, fr. surmettre,
   p. p. surmis, to impose, accuse; sur (see {Sur-}) + mettre to
   put, set, L. mittere to send. See {Mission}.]
   1. A thought, imagination, or conjecture, which is based upon
      feeble or scanty evidence; suspicion; guess; as, the
      surmisses of jealousy or of envy.

            [We] double honor gain From his surmise proved
            false.                                --Milton.

            No man ought to be charged with principles he
            actually disowns, unless his practicies contradict
            his profession; not upon small surmises. --Swift.

   2. Reflection; thought. [Obs.] --Shak.

   Syn: Conjecture; supposition; suspicion; doubt.

Surmise \Sur*mise"\, v. t. [imp. & p. p. {Surmised}; p. pr. &
   vb. n. {Surmising}.]
   To imagine without certain knowledge; to infer on slight
   grounds; to suppose, conjecture, or suspect; to guess.

         It wafted nearer yet, and then she knew That what
         before she but surmised, was true.       --Dryden.

         This change was not wrought by altering the form or
         position of the earth, as was surmised by a very
         learned man, but by dissolving it.       --Woodward.

Source : WordNet®

surmise
     n : a message expressing an opinion based on incomplete evidence
         [syn: {guess}, {conjecture}, {supposition}, {surmisal}, {speculation},
          {hypothesis}]
     v 1: infer from incomplete evidence
     2: imagine to be the case or true or probable; "I suspect he is
        a fugitive"; "I surmised that the butler did it" [syn: {suspect}]