Green’s Dictionary of Slang

(US) money.

1942		W. Winchell On Broadway 2 June [synd. col.] Babs Whitney, the pretty society girl with oodles of moo.
1944		D. Runyon Runyon à la Carte 65: This transaction reminds him that he is very short in the moo department.
1945		F. Fay How To Be Poor 3: You have the ‘moola’ (sometimes abbreviated ‘moo’).
1952		W.R. Burnett Little Men, Big World 71: One day, when he had enough moo to leave the big town, he’d have a hack like that, only maybe pink with cream-coloured upholstery.
1958		Chronicle-Telegram (Elyria, OH) 13 Dec. 4/5: I got to spread moo like butter at Miami.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 41: The mark finally ran out of moo. ‘Take a check?’.