Green’s Dictionary of Slang

woat n.

(US) the lowest example, lit. worst of all time.

Urban Dict. 29 Nov. 🌐 W.O.A.T. Worst Of All Time.
[US]C. Eble (ed.) UNC-CH Campus Sl. Spring 2016 11: WOAT — worst of all times terrible, unappealing: ‘I really don’t like that girl. She’s the woat’.