Fetch missing conclusion to English solution (5)
I believe the answer is:
brine
'solution' is the definition.
(I know that brine is a type of solution)
'fetch missing conclusion to english' is the wordplay.
'fetch' becomes 'bring' (synonyms).
'missing conclusion' means to remove the last letter.
'to english' becomes 'E' (abbreviation).
'bring' with its final letter removed is 'brin'.
'brin'+'e'='BRINE'
(Other definitions for brine that I've seen before include "Salty water" , "Salted water" , "Strong salt-water solution" , "Sea water" , "Seawater" .)