controversy
A long, strong disagreement where people argue about an issue.
A controversy is a prolonged disagreement or argument where people strongly oppose each other's views. When something sparks controversy, it means different groups of people see it in very different ways and feel strongly enough to debate it publicly.
A controversy might erupt at your school if the principal decides to ban recess. Some students and parents would argue this is unfair and hurts kids' health, while others might support it if they think it would add more learning time. Neither side easily backs down because they believe their position is right.
Controversies often involve questions where there's no simple answer that satisfies everyone. Should a new highway cut through a forest? Should a historic statue be removed? People on different sides of a controversy aren't necessarily wrong or bad; they just value different things or interpret facts differently.
The word can describe the disagreement itself (the controversy over the dress code) or a quality something has (a controversial decision). Something controversial tends to divide opinion rather than unite it. Controversy can feel uncomfortable, but it is also one way communities work through difficult questions.