Source : Webster's Revised Unabridged Dictionary (1913)

Rotten \Rot"ten\, a. [Icel. rotinn; akin to Sw. rutten, Dan.
   radden. See {Rot}.]
   Having rotted; putrid; decayed; as, a rotten apple; rotten
   meat. Hence:
   (a) Offensive to the smell; fetid; disgusting.

             You common cry of curs! whose breath I hate As reek
             of the rotten fens.                  --Shak.
   (b) Not firm or trusty; unsound; defective; treacherous;
       unsafe; as, a rotten plank, bone, stone. ``The deepness
       of the rotten way.'' --Knolles.

   {Rotten borough}. See under {Borough}.

   {Rotten stone} (Min.), a soft stone, called also {Tripoli}
      (from the country from which it was formerly brought),
      used in all sorts of finer grinding and polishing in the
      arts, and for cleaning metallic substances. The name is
      also given to other friable siliceous stones applied to
      like uses.

   Syn: Putrefied; decayed; carious; defective; unsound;
        corrupt; deceitful; treacherous. -- {Rot"ten*ly}, adv.
        -- {Rot"ten*ness}, n.

Tripoli \Trip"o*li\, n. (Min.)
   An earthy substance originally brought from Tripoli, used in
   polishing stones and metals. It consists almost wholly of the
   siliceous shells of diatoms.

Source : WordNet®

tripoli
     n 1: a weathered and decomposed siliceous limestone; in powdered
          form it is used in polishing [syn: {rottenstone}]
     2: the capital and chief port and largest city of Libya; in
        northwestern Libya on the Mediterranean Sea; founded by
        the Phoenicians in the 7th century BC [syn: {Tarabulus
        Al-Gharb}, {capital of Libya}]
     3: a port city and commerical center in northwestern Lebanon on
        the Mediterranean Sea [syn: {Tarabulus Ash-Sham}, {Trablous}]