"Ode on a Grecian Urn" writer (5)
I believe the answer is:
keats
(Other definitions for keats that I've seen before include "John --, English poet" , "English odist" , "Author of the poem Ode to a Nightingale, d. 1821" , "To a Nightingale poet" , "Endymion, Lamia poet" .)