Old partner generous, for instance (7)
I believe the answer is:
example
'instance' is the definition.
(I know that instance can be written as example)
'old partner generous' is the wordplay.
'old partner' becomes 'ex' (an ex-partner).
'generous' becomes 'ample' (similar in meaning).
'ex'+'ample'='EXAMPLE'
'for' is the link.
(Other definitions for example that I've seen before include "Characteristic item" , "Standard" , "Illustration or model" , "Illustrative case" , "Thing characteristic of its kind" .)