Against suppressing language of poetry (6)
I believe the answer is:
verses
'poetry' is the definition.
(I've seen this in other clues)
'against suppressing language' is the wordplay.
'against' becomes 'vs'.
'suppressing' means one lot of letters goes inside another.
'language' becomes 'erse' (Erse is an example).
'vs' enclosing 'erse' is 'VERSES'.
'of' is the link.
(Other definitions for verses that I've seen before include "Serves (anag.)" , "Parts of a song" , "Walks" , "Sections of metrical text" , "Sections of poetry" .)