Green’s Dictionary of Slang

1. (US campus) to insult.

1958		Murtagh & Harris Cast the First Stone 106: You’ll only cut your throat with the judge if you try to cut New York’s Finest down.
1967–8		Baker et al. CUSS 103: Cut down Make uncomplimentary remarks about someone.
1981		Eble Campus Sl. Mar. 2: cut down – to criticise or belittle.

2. (US) to open fire.

1969

C. Sellers Where Have All the Soldiers Gone 77: ‘When Charlie cuts down, nobody in this platoon sees Cat Yates’.