I addressed this a bit above, but we can discuss terms. "Feminism" doesn't really mean "a lot of different things." Here's a good definition:
1. The advocacy of women's rights on the basis of the equality of the sexes
2. The theory of the political, economic, and social equality of the sexes
3. The belief that men and women should have equal rights and opportunities
4. The doctrine advocating social, political, and all other rights of women equal to those of men.
(Note that none of this implies "sameness," in terms of the sexes. A feminist can be a woman or a man.)
I would say that "feminism" is an active verb, so therefore, if a person doesn't necessarily consider themselves a "feminist," or advocate for "feminism" doesn't make them a "sexist." A "sexist" would be a person who actively doesn't believe that any of the above is true or necessary, who believes that women are actually inferior to men, and don't deserve the same rights, opportunities, or that they have a "place," which is not . Dictionary is more like: "prejudice, stereotyping, or discrimination, typically against women, on the basis of sex."
"Misogyny," on the other hand, is a hatred of women. That is not the same as being a sexist, though there is usually overlap for the misogynist.
Moxie, every world will have a dictionary entry. That in no way means that this word does not end up being used in a lot of different contexts and with a lot of different meanings -- that is, you can find
other definitions out there, which probably you would think are not as good as this one, but that is the point. Actually, since
you know exactly what you mean by feminism, and it is a subject you know in detail, it all seems obvious and simple and coherent to
you. Other people, with different understandings of the subject, different approaches, etc and etc, won't have this clear picture in mind. And it is this collection of other people and other approaches that leads to the world having a lot of different "meanings".
Even your own given definition is not just one simple thing. It has four different items, most of them making reference to concepts which are not simple. What it means "equality", for example? It obviously cannot be read literally.
Also, those items are not that coherent with each other as well, because from "theory" to "belief" and to "doctrine", well, it is quite a big jump.
And, finally and most importantly, even if we would restrict ourselves to item 3) (by that item I am 100% feminist btw), then you have the question of "how do you enforce it", and for sure anyone's answer to it would shape her/his own understanding of the world.
Surely the world would be in a better place if anyone would agree on the meaning of this word. It would at the very least make the struggle against real misogyny much more effective. But it is obvious for me that someone who sees misogyny everywhere will have a very different understanding of what "feminism" practically means (which is basically my point).