Green’s Dictionary of Slang

honk n.4

[honk v.4 ]

(US drugs) an inhalation of a narcotic.

[US](con. 1967) Bunch & Cole Reckoning for Kings (1989) 21: I’d palmed some salts. [...] and right under his nose I took a honk. Two seconds, and I was a clear-eyed Clarabelle.