Bookish sort (4)
I believe the answer is:
nerd
'bookish sort' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nerd that I've seen before include "Foolish or annoying person" , "Boringly studious person" , "One lacking social skills" , "Socially inept but knowledgeable person" , "Flag on poles; wide (headline)" .)