Discontented rogue who gave information to journalist, could be an asset (8)
I believe the answer is:
resource
'asset' is the definition.
(I know that resource is a type of asset)
'discontented rogue who' is the wordplay.
'discontented' means to remove the middle letters (the word's contents are removed).
'who' becomes 'source' (I am not sure about this - if you are sure you should believe this answer much more).
'rogue' with its centre removed is 're'.
're'+'source'='RESOURCE'
'gave information to journalist could be an' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for resource that I've seen before include "Stock of assets" , "Means of help in project" , "Expedient - supply for use" , "Available reserve to draw on" , "Stock or supply to draw on" .)