Not in the Constitution it doesn’t. Here is a quote from history.com. If this source is biased, I will find a new quote:
The U.S. Supreme Court often has struggled to determine what types of speech is protected. Legally, material labeled as obscene has historically been excluded from First Amendment protection, for example, but deciding what qualifies as obscene has been problematic. Speech provoking actions that would harm others—true incitement and/or threats—is also not protected, but again determining what words have qualified as true incitement has been decided on a case-by-case basis.