polemic n.

1630s, "controversial argument or discussion, a controversy," from French polémique (16c./17c.), noun use of adjective meaning "disputatious, controversial" (see polemic (adj.)). From 1670s as "a disputant, one who writes or argues in opposition to another."

"of or pertaining to controversy," 1640s, from French polémique "disputatious, controversial," or directly from Greek polemikos "of war, warlike, belligerent; skilled in war, fit for service; like an enemy, stirring up hostility," from polemos "war," a word of unknown origin. Related: Polemical (1630s); polemically.