Writer's block starting - editor is discouraged (8)
I believe the answer is:
dampened
'is discouraged' is the definition.
(as in dampening someone's enthusiasm)
'writer's block starting editor' is the wordplay.
'writer' becomes 'pen' (something which writes).
'block' becomes 'dam' (damming is a kind of blocking).
'starting' means one lot of letters go next to another.
'editor' becomes 'ed'.
'pen' put after 'dam' is 'dampen'.
'dampen'+'ed'='DAMPENED'
(Other definitions for dampened that I've seen before include "wet" , "Moistened" .)