But Good Meaning

(idiomatic) To a high degree; very thoroughly; in a most definite manner.

Example: 1992, Catherine Coulter, The Hellion Bride, ISBN 9780515109740, (Google preview):
  Ryder rode beside her, pleased at her pleasure, knowing that he'd surprised her but good.
2000 Oct. 2, Jessica Reaves and Frank Pellegrini, "For Bush, It's an Expectations Game; For Gore, It's Learning From His (Few) Mistakes," Time:
  [T]he debate is a sublime mismatch: He's expected to whip this guy, but good.
2011 Aug. 16, Joe Drape, "Postcards From Saratoga Springs: There’s a Doctor in the Paddock," New York Times (retrieved 16 Aug 2012):
  Dr. Gerald Bortolazzo, or Doc, as he is known, has some story to tell about a horse, his new career as a horseman and how he, if he did not exactly cheat death, fooled it but good.