Idiot crossword writer finally leaving with new editor appointed (8)
I believe the answer is:
assigned
'appointed' is the definition.
(assigning is a kind of appointing)
'idiot crossword writer finally leaving with new editor' is the wordplay.
I cannot really understand how this works, but
'idiot' could be 'ass' (both can mean a stupid person) and 'ass' is present in the answer.
'writer' could be 'ed' (I've seen this in other clues) and 'ed' is found in the answer.
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for assigned that I've seen before include "Allotted or delegated" , "Told" , "Gave a task to someone" , "'Allotted, ascribed (8)'" , "Allotted or appointed to a post" .)