Green’s Dictionary of Slang

the very best.

1994		M. Montague Dread Culture 168: ‘Dat last draw was boom.’ [...] ‘Is a wicked draw of herbs.’.
1997		N. Barlay Curvy Lovebox 33: There ain’t nuthin’ boom about dis poly.
1997		‘Q’ Deadmeat 40: A beautiful, breathtaking woman emerged from the living room [...] She was the living boom.
2003		Dizzee Rascal ‘Round We Go’ 🎵 That’s girl’s the boom t’ing, man.
2017		hubpages.com ‘Roadman Slang’ 4 Jun. 🌐 Boom - great, cool e.g. ‘that party was a boom ting!