Green’s Dictionary of Slang

1. to relax, to ‘lighten up’.

1884		(con. c.1840) ‘Mark Twain’ Huckleberry Finn 19: She worked me middling hard for about an hour, and then the widow made her ease up.
1956		S. Selvon Lonely Londoners 23: Ease me up with the questions old man.

2. as imper.

1923		J. Manchon Le Slang.
1965		E. Bond Saved Scene x: Ease up, louse!
1977		L. Heinemann Close Quarters (1987) 18: Ease up, we got boo-coo and we got all fucken night.
1984		‘Derek Raymond’ He Died with His Eyes Open 45: I said to Charles, ease up on the sauce, cut back on those harpies you go in for.
1992		R. Price Clockers 94: Maz, ease up.
1999		(con. 1979–80) A. Wheatle Brixton Rock (2004) 83: ‘So you can’t offer me one? [a beer]’ snapped Angela. ‘Ease up. I was going to.’.
2001		(con. 1981) A. Wheatle East of Acre Lane 185: ‘Ease up, dread,’ cooled Floyd.
2009		J. Stahl Pain Killers 83: No disrespect, but ease the fuck up, Andre.