Some poetry is hostile (6)
I believe the answer is:
averse
'hostile' is the definition.
(I've seen this before)
'some poetry' is the wordplay.
'some' becomes 'a'.
'poetry' becomes 'verse' (lines written in verse).
'a'+'verse'='AVERSE'
'is' acts as a link.
(Other definitions for averse that I've seen before include "Disinclined - sounds like a poem" , "Disinclined, maybe to hard work" , "Unwilling or disinclined, perhaps to hard work" , "Having a strong dislike" , "Reaves (anag)" .)