If "gullet" refers to the throat/esophagus:
* Mouth: The opening at the beginning of the digestive tract.
* Stomach: The organ where digestion primarily occurs.
* Intestines: The long, tube-like organ following the stomach.
If "gullet" refers to a narrow opening or passage:
* Passageway: A wide, open path or route.
* Spout: A wide opening for pouring liquids.
* Chasm: A deep, wide gap or opening.
If "gullet" is used metaphorically:
* Throat: Can be used figuratively to refer to the space between the mouth and the stomach, but also to the feeling of being choked or constricted.
* Passage: Can refer to a metaphorical path or journey.
Ultimately, the best antonym for "gullet" will depend on the specific meaning and context in which it is used.