Right, here it is — a definition of femme that's inclusive, incisive and intelligible. I doubt I'll ever be able to put it better than this:
femme is dispossessed femininity. It's the femininity of those who aren't allowed to be real women and who have to roll their own feminine gender.
Rolling their own is what cis-femme lesbians did in the fifties. By class and by sexual preference, they were dispossessed of real womanhood. For what woman is complete without money or a man? So they learned how to improvise, how to sew; how to turn a thrift-store sow's ear into a vintage silk purse.
Rolling their own is what contemporary femme dykes do. Invisible in straight spaces and frequently trivialized in queer ones, they must voice their own femininity in a way that does not get shouted down or ignored. No easy task.
Rolling their own is what drag queens and trannies do and have always done. For what woman is complete without hairless skin and a cunt? We too learned how to improvise, and when we were mocked as caricatures of real women, we often became skilled caricaturists, owning the insult, engulfing it.
And this is what femme gay men do, too. Dangerously visible in straight space and often ridiculed in gay male space, femme gay men take the shit from all sides. The straights dish it to them because they're visible. Second-wave feminists dish it to them because they're both feminine and male, and have thus sinned twice. Other gay men dish it to them for acting like, well, chicks.
What these groups share, aside from a fondness for eyeliner, is the illegitimacy of their femininity. That's how I understand femme: badass, rogue, illegitimate femininity. It's the femininity of those who aren't supposed to be feminine, who aren't allowed to be, but are anyway.
— Elizabeth Marston; from her piece Rogue Femininity in the fabulous 2011 anthology Persistence: All Ways Butch and Femme, compiled and edited by Ivan E. Coyote and Zena Sharman.
The contributors include – okay, I'll just list them all in order (I like lists): Anna Camilleri, Kimberly Dark, Miriam Zoila Pérez, Anne Fleming, Karleen Pendleton Jiménez, Leah Lakshmi Piepzna-Samarasinha, Jewelle Gomez, romham padraig gallacher, Zena Sharman, Ivan E. Coyote, Amber Dawn, S.Bear Bergman, Brenda Barnes, Nairne Holtz, Laiwan, Stacey Milbern, B.Cole, Victoria A. Brownworth, Sasha T. Goldberg, Chandra Mayor, Donnelly Black, Redwolf Painter, Sinclair Sexsmith, Belinda Carroll, Zoe Whittall, Elizabeth Marston, Amy Fox, Jeanne Córdova, Rae Spoon, Elaine Miller, Thea Hillman, Bevin Branlandingham, Sailor Holladay, Melissa Sky, Prince Jei and Misster Raju Rage, Ben McCoy, Michael V. Smith, and Debra Anderson, with a foreword by Joan Nestle.
If any of those names mean anything to you at all, you should go and order the book right now!