ETYM Old Eng. gut, got, AS. gut, prob. orig., a channel, and akin to geótan to pour. Related to FOUND to cast.
1. The stomach or belly.
2. (Usually in the plural) An intestine; a bowel; the whole alimentary canal; bowels; entrails.
3. One of the prepared entrails of an animal, esp. of a sheep, used for various purposes.
4. The sac of silk taken from a silkworm (when ready to spin its cocoon), for the purpose of drawing it out into a thread.

1. To empty completely; destroy the inside of.
2. To remove the guts of.

grand unified theory; grand unification theory

1. Arising from one's inmost self; visceral
2. Having strong impact or immediate relevance