Fighting words are words meant to incite violence such that they may not be protected free speech under the First Amendment. The U.S. Supreme Court first defined them in Chaplinsky v New Hampshire (1942) as words which "by their very utterance, inflict injury or tend to incite an immediate breach of the peace. It has been well observed that such utterances are no essential part of any exposition of ideas, and are of such slight social value as a step to truth that any benefit that may be derived from them is clearly outweighed by the social interest in order and morality."
In the decades following Chaplinsky, the U.S. Supreme Court has decided a number of cases which further clarify what speech or actions constitute fighting words.
In Terminiello v. Chicago (1949), the Supreme Court narrowed the scope of what constitutes fighting words. The Court found that words which produce a clear and present danger are unprotected (and are considering fighting words), but words which invite dispute and even cause unrest are protected (and are not considered fighting words).
In Feiner v. People of State of New York (1951), the Supreme Court held that akin to the fighting words doctrine, an incitement of a riot which creates a clear and present danger is also not protected by the First Amendment.
In Texas v. Johnson (1989), the Supreme Court redefined the scope of the fighting words doctrine to mean words that are "a direct personal insult or an invitation to exchange fisticuffs." There, the Court held that the burning of a United States flag, which was considered symbolic speech, did not constitute fighting words.
In R.A.V. v. City of St. Paul (1992), the Supreme Court found that the "First Amendment prevents government from punishing speech and expressive conduct because it disapproves of the ideas expressed." Even if the words are considered to be fighting words, the First Amendment will still protect the speech if the speech restriction is based on viewpoint discrimination.
For academic discussions on the scope of fighting words, see this Washington University Law Review article, this Marquette Law Review article, and this DePaul Law Review article.
[Last updated in November of 2021 by the Wex Definitions Team]