Real Dictionary

polemic
uncountable noun: Polemics is the skill or practice of arguing very strongly for or against a belief or opinion.
variable noun: A polemic is a very strong written or spoken attack on, or defence of, a particular belief or opinion.

polemic in American English
of or involving dispute; controversial
adjective: of or pertaining to a polemic; controversial
noun: a controversial argument, as one against some opinion, doctrine, etc

polemic in British English
adjective: of or involving dispute or controversy
noun: an argument or controversy, esp over a doctrine, belief, etc