Not favouring American poetry (6)
I believe the answer is:
averse
'not favouring' is the definition.
'american poetry' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'poetry' becomes 'verse' ('verse' can be a synonym of 'poetry').
'a'+'verse'='AVERSE'
(Other definitions for averse that I've seen before include "Hostile" , "Loath, reluctant" , "Disinclined, loath" , "A piece of poetry is reluctant" , "Metal rod; card game" .)