Opinionated – Person who is certain about their beliefs and expresses them strongly and often
His opinion she hated (opinionated): hers was correct, she was certain he was wrong and she expressed her views strongly.
Examples of opinionated in a sentence
Despite many of his views being factually and morally wrong, he was too opinionated to ever change.
The opinionated man thought he knew more than the doctor and refused to accept the diagnosis.