Definition of: gag

(gag) noun
1. Any appliance for completely obstructing the vocal organs or restraining speech; hence, any restraint upon free speech or discussion.
2. Something nauseating.
3. An instrument for holding open the jaws during an operation.
4. An interpolation by an actor in a play; a joke, humorous remark, story, etc.; also, a practical joke. [<v.]
—to pull a gag U.S. Slang To perpetrate a hoax; tell an untrue story in a playful spirit.
—v. gagged, gag·ging v.t.
1. To keep from speaking or crying out by means of a gag.
2. To keep from speaking or discussing freely, as by force or authority: to gag the press.
3. To cause nausea in; cause to retch.
4. Surg. To hold open (the mouth) with a gag.
5. Slang To make fun of; hoax.
6. Slang To introduce one's own words or speeches into (a theatrical role): often with up.
—v.i.
7. To heave with nausea; retch.
8. Slang To make jokes or speeches of an improvised nature. [ME gaggen; prob. imit.]