The Collaborative International Dictionary of English v.0.48:

Gag \Gag\, n.
   1. Something thrust into the mouth or throat to hinder
      speaking.
      [1913 Webster]

   2. A mouthful that makes one retch; a choking bit; as, a gag
      of mutton fat. --Lamb.
      [1913 Webster]

   3. A speech or phrase interpolated offhand by an actor on the
      stage in his part as written, usually consisting of some
      seasonable or local allusion. [Slang]

The Collaborative International Dictionary of English v.0.48:

Gag \Gag\, v. t. [imp. & p. p. Gagged; p. pr. & vb. n.
   Gagging.] [Prob. fr. W. cegio to choke or strangle, fr. ceg
   mouth, opening, entrance.]
   1. To stop the mouth of, by thrusting sometimes in, so as to
      hinder speaking; hence, to silence by authority or by
      violence; not to allow freedom of speech to. --Marvell.
      [1913 Webster]

            The time was not yet come when eloquence was to be
            gagged, and reason to be hood winked. --Maccaulay.
      [1913 Webster]

   2. To pry or hold open by means of a gag.
      [1913 Webster]

            Mouths gagged to such a wideness.     --Fortescue
                                                  (Transl.).
      [1913 Webster]

   3. To cause to heave with nausea.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gag \Gag\, v. i.
   1. To heave with nausea; to retch.
      [1913 Webster]

   2. To introduce gags or interpolations. See Gag, n., 3.
      [Slang] --Cornill Mag.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gag
    n 1: a humorous anecdote or remark intended to provoke laughter;
         "he told a very funny joke"; "he knows a million gags";
         "thanks for the laugh"; "he laughed unpleasantly at his own
         jest"; "even a schoolboy's jape is supposed to have some
         ascertainable point" [syn: joke, gag, laugh, jest,
         jape]
    2: restraint put into a person's mouth to prevent speaking or
       shouting [syn: gag, muzzle]
    v 1: prevent from speaking out; "The press was gagged" [syn:
         gag, muzzle]
    2: be too tight; rub or press; "This neckband is choking the
       cat" [syn: choke, gag, fret]
    3: tie a gag around someone's mouth in order to silence them;
       "The burglars gagged the home owner and tied him to a chair"
       [syn: gag, muzzle]
    4: make jokes or quips; "The students were gagging during
       dinner" [syn: gag, quip]
    5: struggle for breath; have insufficient oxygen intake; "he
       swallowed a fishbone and gagged" [syn: gag, choke,
       strangle, suffocate]
    6: cause to retch or choke [syn: gag, choke]
    7: make an unsuccessful effort to vomit; strain to vomit [syn:
       gag, heave, retch]

The Free On-line Dictionary of Computing (19 January 2023):

gag

   Equivalent to choke, but connotes more disgust. "Hey, this
   is Fortran code.  No wonder the C compiler gagged."  See also
   barf.

   [Jargon File]