Opposed to a poem (6)
I believe the answer is:
averse
'opposed to' is the definition.
(I've seen this in another clue)
'a poem' is the wordplay.
'poem' becomes 'verse' (verse is a kind of poem).
'a'+'verse'='AVERSE'
(Other definitions for averse that I've seen before include "Disinclined - sounds like a poem" , "Loath, reluctant" , "Disinclined, maybe to hard work" , "Indisposed" , "Reaves (anag)" .)