A lecturer is a handsome young man (6)
I believe the answer is:
adonis
'a handsome young man' is the definition.
(I've seen this in another clue)
'a lecturer is' is the wordplay.
'lecturer' becomes 'don' (don can mean an academic).
'a'+'don'+'is'='ADONIS'
(Other definitions for adonis that I've seen before include "Said no to the Greek youth" , "beau" , "Extremely handsome young man" , "Extremely attractive young man from Greek mythology" , "Greek idol" .)