Green’s Dictionary of Slang

weedhead n.

[weed n.1 (1d) + -head sfx (4)]

(drugs) a marijuana smoker; also attrib.

[US]Champion Jack Dupree [song title] Weedhead Woman.
[US]R.O. Boyer Dark Ship 152: He was a weedhead, and trigger-happy.
[US]N. Algren Walk on the Wild Side 161: The right arm bore a strange tattoo: A narrow cigarette whose smoke formed a burning boast: king weedhead.
[US]C. Himes Cotton Comes to Harlem (1967) 180: Now I know why the world looks so vague to weedheads.
[US]H.E. Roberts Third Ear n.p.: weed head n. a marijuana smoker.
[UK]S. McConville ‘Prison Language’ in Michaels & Ricks (1980) 525: A smoker of cannabis may be called a pothead or a weedhead.
[US]Rebennack & Rummel Under A Hoodoo Moon 128: I’d show up with a joint in my mouth, signifying I wasn’t no dope fiend, just a weed head.
[US]J. Ellroy Widespread Panic 214: [W]inos, weedheads, K-Y cowboys.