Causing or likely to cause an argument; controversial. The new policy is highly contentious and has sparked debates across the community.
Involving a lot of arguing or disagreement. The meeting was contentious, with both sides refusing to compromise.
Of a person: inclined to argue or provoke disagreement; quarrelsome. He became a contentious neighbor, always ready to complain about the smallest disturbance.
Law: relating to or arising out of a dispute that is contested in court. The firm specialises in both contentious and non-contentious legal work.