The Collaborative International Dictionary of English v.0.48:

Tamper \Tamp"er\, n.
   1. One who tamps; specifically, one who prepares for
      blasting, by filling the hole in which the charge is
      placed.
      [1913 Webster]

   2. An instrument used in tamping; a tamping iron.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

            'T is dangerous tampering with a muse. --Roscommon.
      [1913 Webster]

   2. To meddle so as to alter, injure, or vitiate a thing.
      [1913 Webster]

   3. To deal unfairly; to practice secretly; to use bribery.
      [1913 Webster]

            Others tampered
            For Fleetwood, Desborough, and Lambert. --Hudibras.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tamper
    n 1: a tool for tamping (e.g., for tamping tobacco into a pipe
         bowl or a charge into a drill hole etc.) [syn: tamp,
         tamper, 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: tamper,
         fiddle, monkey]
    2: intrude in other people's affairs or business; interfere
       unwantedly; "Don't meddle in my affairs!" [syn: meddle,
       tamper]