Has a job to use lots of drugs (8)
I believe the answer is:
employee
'lots of drugs' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'has a job to use' is the wordplay.
'has a job' becomes 'ee' (I am not sure about this - if you are sure you should believe this answer much more).
'to' says to put letters next to each other (I've seen this in other clues).
'use' becomes 'employ' ('employ' can be a synonym of 'use').
'ee' after 'employ' is 'EMPLOYEE'.
Can you help me to learn more?
(Other definitions for employee that I've seen before include "Person working for wages or salary" , "Person in office" , "Paid worker" , "Someone on the payroll" , "in work" .)