Bridge partners whack in diamonds, for example (8)
I believe the answer is:
instance
'example' is the definition.
(I know that example can be written as instance)
'bridge partners whack in diamonds' is the wordplay.
'bridge partners' becomes 'ns' (North and South are team-mates in bridge).
'whack' becomes 'tan' (tan can mean to beat or thrash).
'in' means one lot of letters goes inside another.
'diamonds' becomes 'ice' (slang term for diamonds).
'ns'+'tan'='nstan'
'nstan' placed inside 'ice' is 'INSTANCE'.
'for' is the link.
(Other definitions for instance that I've seen before include "Cite as an example" , "Occasion" , "An insect (anag.)" , "Case - isn't acne (anag)" , "Particular example" .)