Green’s Dictionary of Slang

(US campus) a failure; also attrib.

2004		Urban Dict. 27 May 🌐 Jabroni A loser, poser, lame-ass. One who talks the talk, but could never walk the walk.
2014		E. McNamara ‘Authenti Cityin ThugLit Sept. [ebook] ‘Forget that [...] jabroni chef’.
2016		C. Eble UNC-CH Campus Sl. Spring 2016 5: JABRONI — loser.
2024		Bluesky 10 Dec. 🌐 I went to a gathering for a friend in a Brooklyn bar and a bearded jabroni explained to me a VICE article on sexbots for women that he'd read earlier that day. I had written it.