In France, water blended with oil with some care (5)
I believe the answer is:
loire
'in france' is the definition.
('Loire' is part of 'france')
'water blended with oil with some care' is the wordplay.
I cannot really understand how this works, but
an anagram of 'oil' is 'loi' which is located in the answer.
The remaining letters 're' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for loire that I've seen before include "River of central France" , "flower found amid vineyards" , "French runner" , "French river (Orleans, Tours, Nantes)" , "River flowing through Tours and Nantes" .)