Saying something can itself be the doing of it, not just a report on it.
Everyday usage of “performative” treats the word almost as an insult: an action done for an audience rather than out of real conviction, wisdom on display rather than wisdom actually held. That usage borrows a term with real technical content and drains most of it out.
Philosopher J.L. Austin’s 1962 lectures, published as How to Do Things with Words, distinguished performative utterances, saying “I promise,” “I now pronounce you married,” “I name this ship,” from constative ones, statements that can simply be true or false. A performative doesn’t describe an action, it constitutes one, and it succeeds or fails not by matching reality but by meeting “felicity conditions”: the right speaker, the right context, the right procedure, sincerity on the part of everyone involved. Austin later folded this distinction into a broader theory of locutionary, illocutionary, and perlocutionary acts.
The colloquial sense of “performative” as insincere display does trace back to something real in Austin’s framework: an utterance can go through the motions of an act, apologising, believing, grieving, without meeting the sincerity condition Austin identified as one requirement for the act to genuinely succeed. That produces something that looks complete but is hollow, close to, though not identical with, today’s casual usage.
Source: J.L. Austin, How to Do Things with Words (Oxford: Clarendon Press, 1962).