Source : Webster's Revised Unabridged Dictionary (1913)

Conjecture \Con*jec"ture\, v. t. [imp. & p. p. {Conjectured}; p.
   pr. & vb. n. {Conjecturing}.] [Cf. F. conjecturer. Cf.
   {Conject}.]
   To arrive at by conjecture; to infer on slight evidence; to
   surmise; to guess; to form, at random, opinions concerning.

         Human reason can then, at the best, but conjecture what
         will be.                                 --South.