Green’s Dictionary of Slang

(US) useless, hopeless, e.g. a throwaway man.

c.2003		M. Kolenick Homepage 🌐 Although I am retired, I hardly consider myself a ‘throwaway man’; I have worth, I have abilities, I have something to offer to my fellow human beings, something that can benefit society.
2009		W.D. Myers Dope Sick 76: ‘I said the hell with it [...] Stop pretending [...] and be what everybody expected me to be, which was another throwaway dude.