controversial (adj.)

"disputation, debate, prolonged agitation of contrary opinions," late 14c., from Old French controversie "quarrel, disagreement" or directly from Latin controversia "a turning against; contention, quarrel, dispute," from controversus "turned in an opposite direction, disputed, turned against," from contra "against" (see contra (prep., adv.)) + versus "turned toward or against," past participle of vertere "to turn" (from PIE root *wer- (2) "to turn, bend").

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).