That's a trigger word that means different things to different people. To me, it means "someone who advocates that women should have social and political equality with men." Under my definition, I'm a feminist, and I'd be a little surprised if you weren't. What does it mean for you?
That's the issue. "Feminist" and "feminism" alone are too vague to convey any meaningful ideological position. One must elaborate what type or school of feminism they adhere to, in order for a conclusion to be made. Even still, in some cases, it's not enough (e.g. TERFs).
Someone who believes something or another about women's rights, and is statistically more likely to dismiss or suppress any discussion of men's issues.