Green’s Dictionary of Slang

1. (US) very large.

1851		‘How Mike Hooter Came Very Near “Wolloping” Arch Coony’ in T.A. Burke Polly Peablossom’s Wedding 151: I soon see thar was gwine to be the bustinest fight that ever was.
1862		E.K. Wightman letter 12 Sept. in Longacre From Antietam to Fort Fisher (1985) 30: He’s a bustin’ ole feller, ain’t he?
1866		C.H. Smith Bill Arp 118: Ike was at home on a busting furlow.
1901		T. Hammond On Board a Whaler 150: There’s a bustin’ old mud turkle [sic] right along-side.
1912		Wash. Herald (DC) 28 July 4/5: Got a bustin’ good bunch over the in the bleachers today.

2. used as excl. to imply excellence.

2023

Sydney Morn. Herald 18 Nov. 🌐 Bussin: An exclamation indicating appreciation that originated in African American Vernacular English and is widely used by Gen Alpha and Gen Z. Usually describes delicious food.