Unsympathetic prayer came up, loveless (6)
I believe the answer is:
averse
'unsympathetic' is the definition.
(thesaurus)
'prayer came up loveless' is the wordplay.
I cannot quite see how this works, but
'prayer' could be 'ave' (as in Ave Maria) and 'ave' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for averse that I've seen before include "Not keen" , "'Opposed, disinclined (6)'" , "Disinclined or reluctant" , "A line of poetry is opposed" , "Ill-disposed to (a poem?)" .)