Stereotypical bookworm (4)
I believe the answer is:
nerd
'stereotypical bookworm' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nerd that I've seen before include "Anorak (informal)" , "Studious bore" , "In slang, a foolish or uninteresting person" , "Computer geek?" , "One lacking social skills" .)