Greyhound in Fausset's Bible Dictionary

Proverbs 30:31, margin, "girt in the loins," referring to the slenderness of its body at the loins, as if tightly girt for grace and swiftness in running, so that it is classed among the "things which go well." The ancient Egyptian paintings represent such close-girt hounds used in coursing. Gesenius understands Proverbs 30:31 "a war horse with ornamental trappings girt on its loins." Maurer, "a wrestler with loins girt for the struggle."