Green’s Dictionary of Slang

1. (US tramp) to ride atop a freight car, despite it being known by the crew.

1894		J. London Tramp Diary in Jack London On the Road (1979) 31: We held her down all night till we arrived in Truckee at 7 a.m.
1907		J. London Road 32: My, but I was proud of myself! No Croesus was ever prouder of his first million. I was holding her down in spite of two brakemen, a conductor, a fireman, and an engineer.
1927		‘Jargon of the Und.’ in DN V 450: Hold down a train, To ride a train in spite of the opposition of the crew.

2. to keep a job for some time, to occupy.

1901		J. Flynt World of Graft 30: A beggar can ‘hold down’ the city with impunity from one end of the year to the other.
1927		S. Graham N.Y. Nights 43: But here was where my friend from Rhodes belonged, or in local parlance here the islander ‘held down his jahb.’.
1991		(con. 1920s) O.D. Brooks Legs 161: We keep in touch when we’re not together. I been holding this town down waiting to hear from him.

3. (W.I.) of a woman, to control one’s partner, esp. to stop him from having other sexual relationships.

1996

Allsopp Dict. Carib. Eng. Usage.

4. (W.I.) of a man, to assault a woman sexually.

1996

Allsopp Dict. Carib. Eng. Usage.

5. (US campus) to wait; esp. as imper. hold down!

1989

P. Munro Sl. U. 109: Hold down, I’ll be ready in two minutes.

6. (US black) to be in complete control of a situation.

2007

B. Coleman Check the Technique 454: ‘One day I saw RZA doing a block party in a neighborhood that is one of the roughest on Staten Island [...] and he was out there all by himself, holding it down’.