Green’s Dictionary of Slang

(orig. US) to render glamorous, esp. of something/someone plain or old.

1972		Minneapolis Star (MN) 15 Mar. 41/1: Isn’t it time to dress-up, snazz-up and jazz-up for spring?
1982		Indianapolis Star (IN) 29 Aug. 113/1: Snazz up brown-bag lunch [...] Fill your lunch bag with healthy foods only!
1999		Courier (Waterloo, IA) 10 Jan. 47/1: Men are purchasing new vests [...] to snazz up that old tuxedo.
2000		Baltimore Sun (MD) 22 May 34/2: Reach for a pair of Plasma Laces the next time you want to snazz up your sneakers.
2012		Sth Florida Sun Sentinel (Ft Lauderdale, FL) 18 Aug. B2/3: It’s downtown’s debut mural in the city’s attempt to snazz up downtown.