Geeky guy (4)
I believe the answer is:
nerd
'geeky guy' 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 "Geek, anorak (sl.)" , "One lacking social skills" , "Flag on poles; wide (headline)" , "Sort of chap" , "In slang, a foolish or uninteresting person" .)