Instrument for mixing oil in French wine? (6)
I believe the answer is:
violin
'instrument' is the definition.
(I know that Violin is a instrument)
'mixing oil in french wine?' is the wordplay.
'mixing' is an anagram indicator.
'in' is an insertion indicator.
'french wine?' becomes 'vin' ('wine' in French).
'oil' anagrammed gives 'oli'.
'oli' placed into 'vin' is 'VIOLIN'.
'for' is the link.
(Other definitions for violin that I've seen before include "A stringed musical instrument, say a Stradivarius" , "It'a played with a bow" , "An elevated fiddle" , "Instrument with four strings" , "Nigel Kennedy instrument" .)