Meaning

noun a mongrel hog with a thin body and long legs and a ridged back; a wild or semi-wild descendant of improved breeds; found chiefly in the southeastern United States

noun any of several baleen whales of the family Balaenopteridae having longitudinal grooves on the throat and a small pointed dorsal fin

adjective having a sharp narrow back

originFrom razor + back.

Etymology from Wiktionary, CC BY-SA 3.0