Thayer's Greek Lexicon

 1. off scouring, refuse
2. metaph.
  1) the most abject and despicable men
  2) the price of expiation or redemption, because the Greeks used
to apply the term "katharmata" to victims sacrificed to make
expiation for the people, and even to criminals who were
maintained at the public expense, that on the outbreak of a
pestilence or other calamity they might be offered as
sacrifices to make expiation for the state