Someone who isn't afraid to give their personal opinion. It doesn't have to be a bad thing. It's just someone that doesn't stay quiet, if they
don't agree with something.
The only people who see it as bad and attach stigma (
like the other definitions) to it are those that
don't like to hear opinionated people talk.
Yes, you can be opinionated and polite at the same time. Being polite doesn't mean you have to agree with every objectionable thing that's
said.