If you describe someone as cadaverous, you mean they are extremely thin and pale. a tall man with a long, cadaverous face. looking extremely thin, pale, and unhealthy
very thin especially from disease or hunger or cold; "emaciated bony hands"; "a nightmare population of gaunt men and skeletal boys"; "eyes were haggard and cavernous"; "small pinched faces"; "kept life in his wasted frame only by grim concentration"