Poet Whitman (4)
I believe the answer is:
walt
'poet whitman' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for walt that I've seen before include "Mr Disney" , "First name of Disney, cartoon creator" , "-- Whitman, US poet" , "-- Disney, cartoon maker" , "... Disney (film-maker)" .)