Green’s Dictionary of Slang

(orig. US black) very drunk.

1953		Randolph & Wilson Down in the Holler 175: In Washington County, Arkansas, people used to say drunker than Cooter Brown, but nobody seems to know who Cooter Brown was.
1967–70		in DARE.
1978		R.D. Pharr Giveadamn Brown (1997) 130: The last time she had seen Connie, the broad had been leaning against the front fence of a house on 132nd Street, puking her guts out. Drunk as Cooter Brown.
1987		Eble Campus Sl. Oct. 2: drunk as kooter brown – drunk.
1988		H.B. Broome Man Who Had Enemies 79: ‘You’re getting drunk as Cooter Brown,’ he said judgmentally, ‘and I am going to protect you from yourself’.
1990		L. Grizzard Gettin’ It On 349: The time has come to announce the winner of the First Annual Drunk-As-Cooter Brown Award. The award is named for the immortal Cooter Brown, who could get drunker than anybody.
2004		Jim Carruth Gatlan Kids 235: That one on the left is a retard, her mind is equal to a three year old, and that black’s drunk as Cooter Brown.