Thayer's Greek Lexicon

 1. a renter or farmer of taxes
  1) among the Romans, usually a man of equestrian rank
2. a tax gatherer, collector of taxes or tolls, one employed by a
publican or farmer general in the collection of taxes. The tax
collectors were as a class, detested not only by the Jews, but by
other nations also, both on account of their employment and of the
harshness, greed, and deception, with which they did their job.