Drug got from male parliamentarian (4)
I believe the answer is:
hemp
'drug' is the definition.
(cannabis)
'male parliamentarian' is the wordplay.
'male' becomes 'he' (he refers to a man).
'parliamentarian' becomes 'MP' (Member of Parliament).
'he'+'mp'='HEMP'
'got from' is the link.
(Other definitions for hemp that I've seen before include "Narcotic drug" , "Marijuana" , "Grass" , "tea" , "Source of drug" .)