Meaning of countersue

coun•ter•sue

Pronunciation: (koun'tur-s"), [key]
— v., -sued, -su•ing.
—v.t.
  1. to bring a civil action against (one's complainant).
—v.i.
  1. to bring a civil action against one's complainant.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.