Film that's tough about heroin (3,5)
I believe the answer is:
the sting
'film' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'tough about heroin' is the wordplay.
'tough' becomes 'testing' (I can't explain this - if you can you should believe this answer much more).
'about' is an insertion indicator.
'heroin' becomes 'H' (H is a slang term for heroin).
'testing' placed around 'h' is 'THE STING'.
'that's' acts as a link.
Can you help me to learn more?
(Another definition for the sting that I've seen is " film from 1970s".)