1 silence, stifle, still, muffle, stop (up), muzzle, quiet, curb, suppress, repress, restrain, throttle, strangle, check, inhibit, discourage:
The department gagged him, forbidding any press interviews.
2 retch, choke, heave; gasp for air, struggle for breath; US keck:
3 restraint, curb, muzzle, check:
MI5 tried to put a gag on the revelations of the former spy.
1 joke, witticism, jest, quip, pun, gibe, Colloq wisecrack, Slang crack:
He told some gags but nobody found them funny.
2 practical joke, hoax, prank, trick, Colloq fast one:
For a gag, we put a snake in the sergeant's bed.