Extremely desirable drug store (5)
I believe the answer is:
depot
'store' is the definition.
(depot can mean a store or warehouse)
'extremely desirable drug' is the wordplay.
'extremely' means to remove the middle letters (only the extremes of the word are used).
'drug' becomes 'pot' (slang term for cannabis).
'desirable' with its middle removed is 'de'.
'de'+'pot'='DEPOT'
(Other definitions for depot that I've seen before include "Wherein bus drivers" , "Place where buses and trains are kept" , "storeroom" , "Large storage site" , "Supply base" .)