Ye Olde Bull sticks with house wine ultimately (7)
I believe the answer is:
gumshoe
'wine ultimately' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for gumshoe that I've seen before include "footwear" , "Possible US version of Morse" , "Dick" , "Detective (US colloq.)" , "American detective (informal)" .)