Merriam-Webster Collegiate Dictionary - gag

 I. verb  (~ged; ~ging)  Etymology: Middle English ~gen to strangle, of imitative origin  Date: 1509  transitive verb  1.  a. to restrict use of the mouth of by inserting a ~  b. to prevent from exercising freedom of speech or expression  c. to pry or hold open with a ~  2. to provide or write quips or pranks for ~ a show  3. to choke or cause to retch  intransitive verb  1.  a. choke; also to suffer a throat spasm that makes swallowing or breathing difficult  b. retch  2. to be unable to endure something ; balk  3. to make quips  • ~ger noun  II. noun  Date: 1530  1. something thrust into the mouth to keep it open or to prevent speech or outcry  2. an official check or restraint on debate or free speech a ~ rule  3. a laugh-provoking remark or act  4. prank, trick