The adjective polemical describes something related to an argument or controversy. To keep the peace, avoid discussing politics at Thanksgiving, which usually deteriorates into a polemical argument with Uncle Bob. Better stick to football or apple versus pumpkin pie.
Polemical is the adjective form of the noun polemic, which itself comes from the Greek word, polemos, meaning "war." Use polemical to describe a controversy or argument that could end up as a huge conflict, because polemical refers to a major disagreement. The word is often used to describe speech and writing — a polemical discussion or a polemical essay — that usually starts a war of words.