The word dogmatic refers to someone who is assertive and opinionated in their beliefs. If you're looking to describe someone who is also dogmatic, you could use a variety of synonyms depending on the context. For instance, if you want to describe someone as stubbornly holding onto their beliefs, you might use the synonyms tenacious, obstinate, or inflexible. If you want to emphasize the arrogance or dismissiveness in their attitude, you could use the synonyms condescending, haughty, or contemptuous. Alternatively, if you want to describe someone who is confident, articulate, and persuasive in their arguments, you could use the synonyms persuasive, convincing, or compelling. Regardless of what synonym you choose, it's important to remember that being dogmatic isn't always a positive trait, and it's important to remain open to other perspectives and opinions.