A gag rule is a restriction on speech, expression or debate on a particular subject matter. Synonyms for this term are censorship, suppression, prohibition, and muzzling. Each of these words highlights the act of limiting the expression of certain ideas, beliefs or opinions. Censorship refers to the act of controlling content and withholding information while suppression involves silencing of dissenting voices. Prohibition is often used in relation to illegal substances or activities and can also refer to the inability to discuss a particular topic. Muzzling pertains to the act of preventing expression and restricting the free flow of ideas. These synonyms emphasize the negative effects that come with a restriction on the right to express oneself.