Hypothetical professor? (8)
I believe the answer is:
academic
This clue is a double definition.
'hypothetical' is the first definition.
(I've seen this in another clue)
'professor?' is the second definition.
(professor is a kind of academic)
(Other definitions for academic that I've seen before include "Notional" , "Donnish" , "One that's learned" , "fellow" , "Associated with places of higher learning" .)