You fluctuate between different identities. Depending on who it is, it varies on what gender identify you pick. It can be hours, months, or even years.
It's a subset of being bigender. Unlike some bigender people, though, genderfluids have two distinct identities they can be depending on how they feel and the spectrum moves between the two, whereas, bigender people can be two at a time and have more static identities. Bigender people are subset of non-binary, or as we call ourselves, enbies (stands for NB).
A spectrum. That best describes how we feel. It's complicated though, and I don't speak for all of us.
What a genderfluid person ISN'T:
A trender. These thoughts are present mostly since birth. And enbies have been documented throughout history. Enbies have an increased amount of hate and discrimination against them, much more than transgender people do, so this take is even more bizarre; we're fighting to combat it and lessen the hateful and dismissive attitudes we receive.
Wanting to walk into the most convenient bathroom or whatever gendered areas we want. The gendered place depends on what gender identity we are having at the moment, and it doesn't change in a dime. From my experience, unisex bathrooms are my favorite. However, I still won't walk into men's restrooms because of societal pressure and fears.
All the same. Like trans, every enby is different and all our experiences are valid.
Fake. No, it's not. Your feelings are valid and other people don't get to dictate what's real or not. A lot of hate stemming from transphobia also applies to enbies.
Angry people that yell at you for being unexpected to change with the gender that changes within us. We'll try our best to make it easy for you. Only if it's intentional will we get mad.
Has all the benefits of being trans with no downsides. No, it's a real, unique struggle, and gender dysphoria is often a common complication we have.
An effeminate man or a tomboy. Typically, those are cisgender (but it's completely possible to have an effeminate man who identfies as a woman! And vice versa!) and want to be referred to as such, having less issues and complications with what they're called than enbies.
Being genderfluid is like...omg today I don't have male clothes, I feel like being a man, and where can I find a hat that I can cover up my hair (getting my hair cut is a long-term decision as my hair doesn't grow back fast enough in the time span I change my identity so that's a bust)? I have a few pieces of masculine-oriented clothing that I love wearing, I covered up my hair with a hat and I see myself in a mirror with a tank top and I look great but most of my stuff is female-oriented, but sometimes that's amazing to wear as well, like wearing a skirt is comfortable and can feel good when I'm in the mood for it, and tank-tops from uniclo with embedded bras are thumbs up. Identity online is so tough to change for other people since it's much more difficult to express it anonymously and through words only, so that's why either gender works for me, although technically, I don't identify myself as bigender. Maybe I should express it through my signature or profile status somehow. Yeah.
Eat the rich. Burn capitalism. Oppose fascism. Fight hate. Corporations aren't people. Black Lives Matter. Global warming kills more than terrorism. Wear a mask. Feminism is still needed. Trans and enby recognition and rights. All sexual orientations are valid. Donald Trump is a turd. The Republican Party is a proto-fascist cesspool.