Green’s Dictionary of Slang

(orig. US) very much so, extremely.

1942		‘Marienne’ ‘Solid Meddlin’’ in People’s Voice (NY) 28 Mar. 31/1: He’s first maestro Lionel [Hampton] on vibes and drums, but good!!
1953		J. Thompson Alcoholics (1993) 54: Got the whole down on him but good and wound up in jail.
1959		‘Paul Merchant’ ‘Sex Gang’ in Pulling a Train’ (2012) [ebook] He was hung up but good this time.
1967		W. Murray Sweet Ride 32: They tore her up. But good.
1978		A. Maupin Tales of the City (1984) 12: If you can’t deal, with your own sexuality, hon, you’re gonna get screwed but good in this town.
2001		Source Aug. 32: Falling in love with a stripper will fuck ya mind up but good, leaving you susceptible to all types of mishaps.
2004		(con. 1960s-70s) T. Taylor Top Fellas 2/1: Occasionally one of the gang-busters found himself in the worng place [...] and got his spuds cooked but good.