Writer to sample verse (6)
I believe the answer is:
poetry
'verse' is the definition.
(I know that verse can be written as poetry)
'writer to sample' is the wordplay.
'writer' becomes 'poe' (Edgar Allan Poe).
'to sample' becomes 'try' ('try' can be a synonym of 'sample').
'poe'+'try'='POETRY'
(Other definitions for poetry that I've seen before include "Work by Keats or Shelley, say" , "The product of Tennyson or Longfellow" , "rhyme" , "'The Raven'?" , "Verses" .)