Frozen marijuana drink (4,3)
I believe the answer is:
iced tea
'drink' is the definition.
(iced tea is a kind of drink)
'frozen marijuana' is the wordplay.
'frozen' becomes 'iced' (I've seen this before).
'marijuana' becomes 'tea' (slang term for the drug).
'iced'+'tea'='ICED TEA'
(Other definitions for iced tea that I've seen before include "Chilled drink" , "Cold summer drink" , "Cool drink" .)