Teacher, briefly (4)
I believe the answer is:
prof
I believe this clue is a double definition.
'teacher' is the first definition.
(I've seen this before)
'briefly' is the second definition.
(I have seen 'Academic briefly' mean 'prof' so perhaps 'briefly' could also mean 'prof')
(Other definitions for prof that I've seen before include "Academic briefly" , "High-ranking university academic (abbr)" , "Top academic (informal)" , "head of dept at uni" , "teacher" .)