"You canker blossom!" 3 Shakespearean Insults
1590s, altered from kitgut, probably from obsolete kit (n.2) "fiddle" + gut (n.). It was made from the intestines of sheep.
catgut cat·gut (kāt'gŭt')n. A tough, thin cord made from the treated and stretched intestines of certain animals, especially sheep, and used for surgical ligatures.