go bad

VERB
6 LETTERS · STARTS WITH G

go bad is a valid 6-letter word worth 9 points in Scrabble and 11 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
G2O1B3A1D2
2 + 1 + 0 + 3 + 1 + 2 =9 PTS
DOUBLE WORD → 18TRIPLE WORD → 27
MEANING

What does go bad mean?