Green’s Dictionary of Slang

1. (US campus) to have a party, to ‘let oneself go’; to dance.

1929		Blind Lemon Jefferson ‘Saturday Night Spender Blues’ 🎵 But as soon as night come, I go out for a spendin’ fling. / I have five, six and seven women, and a whole lots of corn / [...] / Then we go out and break ‘em down, honey till early morn.
1933		W. Wilson ‘Gimme a Pigfoot’ 🎵 Old Hannah Brown from crosstown / Gets full of corn and starts breaking ‘em down / [...] / You can hear old Hannah say / Gimme a pigfoot and a bottle of beer / Send me, gate, I don’t care.
1936		Tampa Reds [Hudson Whittaker] ‘Let’s Get Drunk and Truck’ 🎵 I know your other man is out of town / My other woman, she’s not around / Now is the time to break ’em down / Let’s get drunk and truck.
1937		‘Big Bill’ Broonzy ‘Down in the Alley’ 🎵 Don’t give me no woman, from uptown / The wimmen down the alley really breaks ’em down.
1996		Eble Campus Sl. Mar. 1: break it down – dance, usually to a funky beat.
2012		C. Eble (ed.) UNC-CH Campus Sl. 2011.

2. (US black) to get excited, to become emotional.

1937		B. Goodman This Thing Called Swing 3: break it down!: Get hot! Swing it!
1959		Jazz: A Quarterly of Amer. Music Fall 284: ‘Break it down’ was reported to be Harlem’s pet expression of 1933, and was synonymous with ‘get hot’.
1993		Snoop Doggy Dogg ‘Lodi Dodi’ 🎵 Why don’t you give me a play / So we can break it down the Long Beach way.