Green’s Dictionary of Slang

wasteman n.

(UK black teen) a fool.

Urban Dict. 30 Mar. [Internet] Wasteman insult - someone who does nothin with their life (or nothing much).
[UK]BBC News ‘Report on Teenage Slang’ 11 Mar. [radio] wasteman = idiot, fool.
[UK]Independent 5 Jan. [Internet] There are insults and terms of disapproval such as wasteman, gasman, neek (both nerd and geek), dinter and bell for males.
[UK]Skepta ‘Text Me Back’ [lyrics] I ain’t one of them wasteman tryna flex on Insta.
Masicka ‘Hard Fi Dead’ [lyrics] Pussy deh a wasteman weh gyal a piss ’pon.
poster at anti-Trump demo 30 Jan. Trump Is a Wasteman.
[Can]Globe & Mail (Toronto) 4 Aug. [Internet] ‘They’ll say, “Oh, this guy’s such a waste yute [useless person]”’.