More revolting, gratuitous, extreme fiction found in Iraqi city, in the past (6)
I believe the answer is:
Here is my best explanation:
'more revolting' is the definition.
(I've seen this before)
'gratuitous extreme fiction found in iraqi city in the past' is the wordplay.
I cannot really see how this works, but
'fiction' could be 'lie' (I've seen this in other clues) and 'lie' is present in the answer.
This may be the basis of clue (or it may be nonsense).