The essayist was a gentle creature (4)
I believe the answer is:
lamb
This clue is a double definition.
'the essayist' is the first definition.
(I've seen this in another clue)
'a gentle creature' is the second definition.
(I've seen this in another clue)
'was' acts as a link.
(Other definitions for lamb that I've seen before include "Young sheep" , "Noted essayist - symbol of innocence" , "Exemplar of innocence" , "author?" , "A follower" .)