Green’s Dictionary of Slang

mad n.

(US) a state of anger.

1914		T. McNamara Us Boys 11 July [synd. cartoon strip] Maybe I kin bull him out of his mad and make him invite me.
1960		J. Brosnan Long Season 132: ‘I’ve got just enough of a mad on to cover Enright; and that’s no small task’.
1970		D. Jenkins Saturday’s America 260: [H]e started working up his mad for the game; putting on his ‘game face’.
2005		W.D. Myers Autobiog. of My Dead Brother 159: I tried to get my mad going again, but it was hard.
2009		W.D. Myers Dope Sick 157: I could hear myself thinking that my mad wasn’t working with him.

In phrases

have a mad on (v.)

(US) to conduct an argument.

1930		W. Winchell On Broadway 1 Jan. [synd. col.] Clive Weed, the editorial cartoonist, and the Eve’g World have a mad on.
1935		M. Fulcher ‘Believe Me’ in Afro-American (Baltimore, MD) 16 Mar. 12/5: Radie Broome Adkins [...] has a mad-on with the ed of the Memphis World.