Bookish PhD beset by desire to make a comeback (5)
I believe the answer is:
nerdy
'bookish' is the definition.
(I've seen this in another clue)
'phd beset by desire to make a comeback' is the wordplay.
'phd' becomes 'dr' (I can't justify this - if you can you should believe this answer much more).
'beset by' indicates putting letters inside ('beset' could historically mean 'cover').
'desire' becomes 'yen' (yen can mean a longing or desire).
'to make a comeback' says the letters should be written in reverse.
'dr' placed within 'yen' is 'ydren'.
'ydren' written backwards gives 'NERDY'.
Can you help me to learn more?
(Other definitions for nerdy that I've seen before include "Geeky" , "Boringly studious" , "obsessive" , "Bright but socially inept" .)