Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
gut (n.)
refers to the belly or belly and bowels, as in the Informal and Conversational I have a pain in my gut. Figuratively, in the plural, the guts are the seat of courage, daring, nerve, and pluck, and the slang term sand, as in She has a lot of guts, and she won’t back down. In this sense the word is Conversational and Informal at best and is therefore frequently and tiresomely replaced by a euphemism and cliché, intestinal fortitude. Best advice: use guts, courage, determination, or another explicit quality and skip all tired metaphors and frozen figures.
