Feminism is power - the power to be the best me I am capable of being. It is the power to try anything my skill set will allow me to try without anyone's telling me, based on my sex, what that is. It is the power to be a full member of the human race.
DJ Dual Core of DJ Dual Core's Old Mixed Tapes:
...at the core of feminism we find the idea that women, as a group, are treated unjustly relative to men and that this should change... You either believe that or you don't. If you do, you are are a feminist. If not, you are not. (more here)
Valerie Connors, President of Circle K International, University of South Florida Sarasota-Manatee:
...feminism is about women having the freedom to make the same choices as men. It's about lifting that oppressively low ceiling that so many women bump their heads on way too often. It's about women being able to feel safe in and out of their homes. And finally, it's about men and women truly respecting and loving each other. (more here and here)
Earlgreyrooibos of This is What a Feminist Blogs Like:
Feminism means recognizing that the way society is set up is not equal, and that the reasons for those inequalities can run deep, stretching across class, gender, and individual beliefs. In addition, feminism is about extended critical thinking beyond one’s own personal experience. Feminism is not an individualist, everyone-for-themselves movement... Feminism requires that we try to understand everyone’s perspectives. (more here)
Veronica of Viva La Feminista:
My definition is that feminism is a political movement where women and men seek equality and equity in society between women and men. Equal pay for equal work. Equal opportunities.
Feminist Gal of Oh, You're a FEMINIST?!:
I absolutely agree with Jessica Valenti on this one and say that my feminism is the social, political, and economic equality for women (more here)
Newscat, quoting Amanda Marcotte of Pandagon:
Feminism is "...an idea, not a movement... It’s really a very simple idea, the idea that men and women are equals and should be treated as equals. How you interpret that is always going to be dependent on your other beliefs, interests, and ideas."
Dr. W. of Professor, What If?:
Charlotte Bunch’s argument that feminism is “an entire worldview or gestalt, not just a laundry list of ‘women’s issues’ is another favorite of mine. As Bunch argues, “Feminist theory provides basis for understanding every area of our lives, and a feminist perspective can affect the world politically, culturally, economically, and spiritually.” Yes, it certainly can. And once you re-place your feminist lenses stolen from you by the culture/society/history/institutional white supremacist heteronormative imperialist patriarchal matrix that defines ‘reality,’ you will never look at the world in the same way again. (more here)
Feminism is the effort to save both genders from the sexual stereotypes that have traditionally limited them.
Feminism is challenging the antiquated notion of patriarchy.
We'd love to have more definitions, so if you don't see one that fits, leave it in the comments!
UPDATE: Here are a couple of definitions from late-comers that are not-to-be-missed:
In my view, I see the objective of feminism to allow women complete self-determination, and that there is nothing anti-male about that. If a man wants to interact with a woman, he has to be willing to do it on her terms without lying and without coercion or threats of coercion implicit or explicit. The same is true for men, complete self-determination. If a woman wants to interact with a man, she has to do it on his terms too, but those terms can't include coercion.
bell hooks got it right. Feminism, the political movement to end sexism.
I spell it out in three parts:
1) Acknowledging the history of and current effects of sexism (ex. pay gap, sexual violence, work-family balance, motherhood penalties,...).
2) Acknowledging that sexism is morally and politically harmful.
3) A commitment to some sort of action to fight sexism.