gut

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The digestive tract or a portion thereof, especially the intestine or stomach.
• noun The embryonic digestive tube, consisting of the foregut, the midgut, and the hindgut.
• noun The bowels or entrails; viscera.
• noun Innermost emotional or visceral response.
• noun The inner or essential parts.
• noun Slang Courage; fortitude.
• noun Slang A gut course.
• noun Thin, tough cord made from the intestines of animals, usually sheep, used as strings for musical instruments or as surgical sutures.
• noun Fibrous material taken from the silk gland of a silkworm before it spins a cocoon, used for fishing tackle.
• noun A narrow passage or channel.
• noun The central, lengthwise portion of a playing area.
• noun The players occupying this space.
• transitive verb To remove the intestines or entrails of; eviscerate.
• transitive verb To extract essential or major parts of.
• transitive verb To destroy the interior of.
• transitive verb To reduce or destroy the effectiveness of.
• adjective Arousing or involving basic emotions; visceral.
• idiom (gut it out) To show pluck and perseverance in the face of opposition or adversity.

from The Century Dictionary.

• To take out the entrails of; disembowel; eviscerate.
• To plunder of contents; destroy or strip the interior of: as, the burglars gutted the store.
• noun Either the whole or a distinct division of that part of the alimentary canal of an animal which extends from the stomach to the anus; the intestinal canal, or any part of it; an intestine: as, the large gut; the small gut; the blind gut, or cæcum.
• noun In the plural, the bowels; the whole mass formed by the natural convolutions of the intestinal canal in the abdomen.
• noun In biology, the whole intestinal tube, alimentary canal, or digestive tract; the enteric tube, from mouth to anus. See enteron, stomodæum, proctodæum.
• noun The whole digestive system; the viscera; the entrails in general: commonly in the plural.
• noun The substance forming the case of the intestine; intestinal tissue or fiber: as, sheep's gut; calf-gut.
• noun A preparation of the intestines of an animal used for various purposes, as for the strings of a violin, or, in angling, for the snood or leader to which the hook or lure is attached.
• noun A narrow passage; particularly, a narrow channel of water; a strait; a long narrow inlet.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To take out the bowels from; to eviscerate.
• transitive verb To plunder of contents; to destroy or remove the interior or contents of.
• noun A narrow passage of water.
• noun An intenstine; a bowel; the whole alimentary canal; the enteron; (pl.) bowels; entrails.
• noun One of the prepared entrails of an animal, esp. of a sheep, used for various purposes. See Catgut.
• noun The sac of silk taken from a silkworm (when ready to spin its cocoon), for the purpose of drawing it out into a thread. This, when dry, is exceedingly strong, and is used as the snood of a fish line.
• noun See CÆcum, n. (b).

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The alimentary canal, especially the intestine.
• noun informal The abdomen of a person, especially one that is enlarged
• noun uncountable The intestines of an animal used to make strings of a tennis racket or violin, etc.
• noun A person's emotional, visceral self.
• noun this sense?) Any small internal organs.
• noun in the plural The essential, core parts.
• noun in the plural Ability and will to face up to adversity or unpleasantness.
• noun informal A gut course
• verb transitive To eviscerate.
• verb transitive To remove or destroy the most important parts of.
• adjective Made of gut, e.g., a violin with gut strings
• adjective Instinctive, e.g., a gut reaction