Pie contains nuts, for example (4,2,5)
I believe the answer is:
case in point
'example' is the definition.
(case in point is a kind of example)
'pie contains nuts' is the wordplay.
'nuts' indicates an anagram (nuts can mean crazy).
'pie'+'contains'='piecontains'
'piecontains' with letters rearranged gives 'CASE IN POINT'.
'for' acts as a link.
(Other definitions for case in point that I've seen before include "Example of what is under discussion" , "Particular example" .)