From Longman Dictionary of Contemporary Englishreeferree‧fer /ˈriːfə $ -ər/ noun [countable] old-fashioned MDDa cigarette containing the drug marijuana SYN joint
Examples from the Corpus
reefer• Renate was sitting on the edge of the king-sized bed with the black sheets, smoking a reefer.• Top Shop is doing a brisk trade in reefer jackets and A-line car coats.• Another source of inspiration was the naval reefer jacket of the late nineteenth century.Origin reefer (1900-2000) Perhaps from → REEF2 (in the sense “to roll something up”), or perhaps from Mexican Spanish grifo “(someone who smokes) marijuana” 