Definitions:
the stomach or belly

used in reference to a feeling or reaction based on an instinctive emotional response rather than considered thought

personal courage and determination; toughness of character

fibre made from the intestines of animals, used especially for violin or racket strings or for surgical use.

a narrow passage or strait.

remove the intestines and other internal organs from (a fish or other animal) before cooking it.

cause (someone) to feel extremely upset or disappointed