It can bring conviction (5)
I believe the answer is:
trial
'conviction' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'it can' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'can' becomes 'rial' (I can't explain this - if you can you should give a lot more credence to this answer).
't'+'rial'='TRIAL'
'bring' acts as a link.
Can you help me to learn more?
(Other definitions for trial that I've seen before include "Troublesome thing; test" , "Ordeal or court case" , "pain in the neck" , "Court appearance on charge - it's an ordeal" , "Court examination; test" .)