Water spilt with ease (5,3)
I believe the answer is:
white sea
'water' is the definition.
(I know that White Sea is a inlet)
'spilt with ease' is the wordplay.
'spilt' is an anagram indicator.
'with'+'ease'='withease'
'withease' anagrammed gives 'WHITE SEA'.
(Other definitions for white sea that I've seen before include "Russian waters" , "Inlet of the Arctic" , "A quantity of salt water" .)