Spit in the sea (7)
I believe the answer is:
sandbar
This could be a double definition.
'spit' is the first definition.
The answer and definition can be both natural objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'sea' is the second definition.
The definition and answer can be both natural objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'in the' acts as a link.
Can you help me to learn more?
(Another definition for sandbar that I've seen is " Danger for sailors".)