Fashionable position, for example (8)
I believe the answer is:
'example' is the definition.
'fashionable position' is the wordplay.
'fashionable' becomes 'in' (similar in meaning).
'position' becomes 'stance' (stance is a kind of position).
'for' is the link.
(Other definitions for instance that I've seen before include "Case or example from ancients" , "Case - isn't acne (anag)" , "Particular example" , "Occasion" , "Exemplify" .)