What does "performative" mean?

Your performance can be performative. Performance is the action, performative is a descriptor of the action. Usually "Performative" refers to a performance that is intended more as a gesture than a meaningful action. It's just going through the motions.

If I behave in accordance with my beliefs, that is performance, no other descriptors are needed. If I behave in a way that doesn't align with my beliefs, solely to satisfy others, it is performative.

It can also be used to describe token actions, things that look bigger than they actually are, "throwing a bone," so to speak, but we're starting to get out of philosophy a bit here.

From what I understand of Butler's theories of performativity, albeit quite little, you can only be an identity through the act of preforming the cultural standards of that identity. And the way you perform the performance of your identity, in its self redefines that identity, making that identity performative. That's probably off the mark, I never got into the prerequisite Focault needed to understand Butler's work.

I do know in an economic sense, performative theory states that an economic theory doesn't need to be inherently true, but rather people need to believe that it is true which will result in the theory being true, like a self-fulfilling prophecy.

I take it to mean actions or choices made to satisfy a hegemony in lieu of or irrespective of one's actual beliefs or ethics.

To answer the question directly, something you do as a performance is something that has the characteristic of being performative.

Full disclosure, I am not a philosopher, nor do I have any meaningful level of schooling in philosophy. I'm sure there is nuance I'm missing here.

When Butler talks about performativity, it is the discussion of identity as learned behaviors and social conventions. Specifically, gender identity isn't a natural or pre-existent essential element of who you are. Gender isn't something you are, it is something you do. One doesn't do gender because of some characteristic of themselves that predisposes them to acting a specific way. You do gender because you are socialized to perform a "gender" in society, and this performance is something that is enforced by other folks who both relate to and are a part of the dominant gender culture. Gender exists as an identity as a result of these performances and resultant social and political imaginaries, institutions, and linguistic traditions.

Performativity theory, if summed up in a sentence, would be: We don't perform gender because of our pre-existing identity, rather our identity is the result of the performance of gender.

Performativity theory has sometimes been casually and dishonestly used by some flavors of TERF-ism that use gender abolition (the "undoing of gender") as a pre-text for transphobia. Of course, most performativity theorists have a trans-positive interpretation of performativity theory, namely Butler herself [1]. It's important to know that not everyone agrees with performativity theory. Gender Trouble barely mentions the experiences of trans people at all. It's also important to note that people experience gender in vastly different ways. I'm not really well equipped to dig into which metaphysical frameworks of gender have more merit. Honestly, at least as far as my politics and gender identity go, the metaphysics are largely irrelevant to me.

[1] https://www.versobooks.com/blogs/2009-judith-butler-on-gender-and-the-trans-experience-one-should-be-free-to-determine-the-course-of-one-s-gendered-life

I don't read much philosophy (or at least not formal philosophy), but I take it as saying things for some reason other than to convey what you think is true about the world.

Level 1: "There's a lion across the river." = There's a lion across the river.
Level 2: "There's a lion across the river." = I don't want to go (or have other people go) across the river.
Level 3: "There's a lion across the river." = I'm with the popular kids who are too cool to go across the river.
Level 4: "There's a lion across the river." = A firm stance against trans-river expansionism focus grouped well with undecided voters in my constituency.

(Source)

One reason you might say something without meaning it literally is that you are an actor in a performance, but performative statements go well beyond that. See also jokes, lies, and bullshit (indifference to the truth).

This isn't directly related, but it reminds me that words can be used in all sorts of ways beyond their literal meaning. Here's a quote from Inside the Cells of the Eggplant:

We use words as tools to get things done; and to get things done, we improvise, making use of whatever materials are ready to hand. If you want to whack a piece of sheet metal to bend it, and don’t know or care what the “right” tool is (if there even is one), you might take a quick look around the garage, grab a large screwdriver at the “wrong” end, and hit the target with its hard rubber handle. A hand tool may have one or two standard uses; some less common but pretty obvious ones; and unusual, creative ones. But these are not clearly distinct categories of usage.

Words go the same way. Almost any word can be used to mean almost anything, in some context. You could play this as a challenge game… How about “The eggplant is a straw hat, and the spinach is yelling about politics”?

We’re in the kitchen of a vegetarian restaurant. A table’s entrees are ready, and the server who took the order is explaining to the one who will deliver the meal which diner gets which dish. One customer’s flamboyant straw hat is a salient, unambiguously identifying feature; you can see it all the way across the room. The other probably needs to turn up a hearing aid; you can hear their opinions about cultural appropriation all the way across the room.

Let me just mention that Judith Butler has a specific theory of gender in mind, but there is a wider philosophical idea of performative utterances, i.e., speech acts. A speech act is roughly one that makes itself come true, e.g. "I assert that you are a murderer!" is, in and of itself, an assertion that the interlocutor is a murderer; "I do" or "I now declare you husband and wife" in the context of a marriage ceremony is a statement which brings about the assent to marriage, i.e. it's a kind of ritual speech that performs the act of entering into marriage or formally recognizing such a marriage.

This is probably not what Judith Butler had in mind, but they are examples of what philosophers of language would call performative speech.