gag: [15] Middle English gaggen meant ‘strangle, suffocate’, so the word started out with strong connotations that seem to have become submerged in local dialects as it came to be used more commonly in the milder sense ‘obstruct someone’s mouth’. In the 20th century, however, they have re-emerged in the intransitive sense ‘choke’. It is not clear how the 19th-century noun sense ‘joke’ is connected, if at all. As for the word’s source, it is generally said to have originated as an imitation of someone retching or choking.
