A manifesto is a written statement in which a group says what they believe and what they mean to do. The classic use is a political party before an election: here is our picture of the country, and here are the changes we will try to make. Artists, writers, and other movements have written manifestos too — not only politicians — so the word jumped from politics into art and protest. It feels formal. You would not call a chat message a manifesto unless you were joking. There is a rare verb, to manifesto, meaning to put out such a statement, but almost nobody uses it in ordinary English; you will meet the noun. It is a close family member of manifest (“clear, out in the open”): both go back to a Latin word for making something public. Manifesto came in through Italian in the 1600s. Though actually, a real manifesto is often longer and vaguer than the proud title suggests — parties write them to sound sure, and then life gets messy.