12 across
Possible
result
of
investigation:
academic
with
double
character
(5)
Possible result of investigation: academic with double character (5)
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
The definition is Possible result of investigation, since proof is what you might end up with after digging into something. You've got PROF (your academic) wrapped around OO (the letter "O" twice over, your "double character").