Unexpectedly, I came across rogue professor (8)
I believe the answer is:
academic
'professor' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'unexpectedly i came across rogue' is the wordplay.
'unexpectedly' indicates an anagram.
'across' is an insertion indicator.
'rogue' becomes 'cad' (I've seen this in another clue).
'i'+'came'='icame'
'icame' with letters rearranged gives 'aemic'.
'aemic' going around 'cad' is 'ACADEMIC'.
Can you help me to learn more?
(Other definitions for academic that I've seen before include "Scholar - relating to a college" , "Scholarly or of a university" , "Scholarly as opposed to practical (8)" , "Well-read" , "Unimportant" .)