"Any man's death diminishes me" writer (5)
I believe the answer is:
donne
'any man's death diminishes me writer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for donne that I've seen before include "basic assumption" , "John -, English poet" , "English preacher and metaphysical poet, d. 1631" , "Writer of poetry" .)