Green’s Dictionary of Slang

chef v.

[chef n. (1)]

1. (US drugs) to prepare opium for smoking.

[US]Amer. Mag. 77 June 31–5: Chef me up a few extra big ones to-night. I’ll take more to-night, for this will be about my last smoke. I’m going to quit.
[US]M. West Babe Gordon (1934) 246: Pinhead burned a heavy incense to smother the fumes of the drug [...] she knew that he was ‘cheffing’ for Money Johnson.
[US]Berrey & Van den Bark Amer. Thes. Sl.
[US]Goldin et al. DAUL 42/2: Chef, v. To serve as a chef. Chef left and right. To have the gift of ambidexterity in tending the opium pipe.
[US]J.E. Schmidt Narcotics Lingo and Lore.
[US](con. 1930s) Courtwright & Des Jarlais Addicts Who Survived 329: I could chef and it made you, like, the king of the walk. You were the main guy. Especially me: I had money, I had stuff.

2. (US drugs) to cook v.1 (6g) crack cocaine from cocaine and baking soda.

Jeezy ‘Let Em Know’ 🎵 My partner pulled up, I had to chef it up, hibachi.
Central Cee ‘Pinging’ 🎵 The young bulls cheff and swing it.

In phrases

chef down/up (v.) (also cheff (up))

(UK Black) to use a knife to attack, fig. use of ‘chop up’ .

67 ‘Low But Bait’ 🎵 Don't get in my way / I’ll turn insane then chef up the place.
67 ‘Milly Rock’ 🎵 I will chef man down and smoke weed then laugh about it / 67 we some savage niggas, no way around it.
Loski ‘Drill’ 🎵 I catch one trippin’ / Chef man down I’m Michelin starred.
[UK]T. Thorne (ed.) ‘Drill Slang Glossary’ at Forensic Linguistic Databank 🌐 Cheffed (up)- stabbed, killed.