This time the poetry literally ends unfavourably (9)
I believe the answer is:
adversely
'unfavourably' is the definition.
Both the answer and definition are adverbs. Maybe there's an association between them I don't understand?
'this time the poetry literally ends' is the wordplay.
'this time' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'the poetry' becomes 'verse' (synonyms).
'ends' suggests removing the centre.
'literally' with its centre removed is 'ly'.
'ad'+'verse'+'ly'='ADVERSELY'
Can you help me to learn more?
(Another definition for adversely that I've seen is " Negatively".)