Prescription for Verity? (5,4)
I believe the answer is:
truth drug
'prescription for verity?' is the definition.
The definition suggests a singular noun which matches the answer.
'prescription for verity?' is the wordplay.
'prescription' becomes 'drug' (I can't justify this - if you can you should give a lot more credence to this answer).
'for' means one lot of letters go next to another (I've seen this in other clues).
'verity?' becomes 'truth' (synonyms).
'drug' after 'truth' is 'TRUTH DRUG'.
Can you help me to learn more?
(Other definitions for truth drug that I've seen before include "Supposed means of preventing lying" , "that may provide required information" .)