A controversy is a dispute or argument in which people express strong opposing views. When a popular TV show kills off a well-loved character, there's bound to be a lot of controversy.
Controversy means a quarrel (often public) involving strong disagreement, but the topic can be as unimportant as a new movie. There might be a controversy in the pages of fashion magazines over whether shorter hems are really in style, or about wearing white after Labor Day. Controversy is from the Latin contrōversus, "turned in an opposite direction," from the prefix contrā, "against," plus versus, a form of vertere, "to turn."