Left Marie Celeste? (9,4)
I believe the answer is:
abandoned ship
'celeste?' is the definition.
Both the definition and answer are singular nouns.
Perhaps there's a link between them I don't understand?
'left marie' is the wordplay.
'left' becomes 'abandoned' (abandoning is a kind of leaving).
'marie' becomes 'ship' (I can't justify this - if you can you should give a lot more credence to this answer).
'abandoned'+'ship'='ABANDONED SHIP'
Can you help me to learn more?
(Other definitions for abandoned ship that I've seen before include "left failing organisation" , "Took to the lifeboats" , "Hurriedly left an organisation or enterprise" .)