Source : Webster's Revised Unabridged Dictionary (1913)

Tamper \Tamp"er\, n.
   1. One who tamps; specifically, one who prepares for
      blasting, by filling the hole in which the charge is
      placed.

   2. An instrument used in tamping; a tamping iron.

Tamper \Tam"per\, v. i. [imp. & p. p. {Tampered}; p. pr. & vb.
   n. {Tampering}.] [A corruption of temper.]
   1. To meddle; to be busy; to try little experiments; as, to
      tamper with a disease.

            'T is dangerous tampering with a muse. --Roscommon.

   2. To meddle so as to alter, injure, or vitiate a thing.

   3. To deal unfairly; to practice secretly; to use bribery.

            Others tampered For Fleetwood, Desborough, and
            Lambert.                              --Hudibras.

Source : WordNet®

tamper
     n : a tool for tamping (e.g., for tamping tobacco into a pipe
         bowl or a charge into a drill hole etc.) [syn: {tamp}, {tamping
         bar}]
     v 1: play around with or alter or falsify, usually secretively or
          dishonestly; "Someone tampered with the documents on my
          desk"; "The reporter fiddle with the facts" [syn: {fiddle},
           {monkey}]
     2: intrude in other people's affairs or business; interfere
        unwantedly; "Don't meddle in my affairs!" [syn: {meddle}]