The most common and most likely answer to this crossword clue is the 4 letter word WONK
W
O
N
K
More clues leading to the result WONK
Buddy explains!

The straight part
We know that "geeky type" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case geeky type = wonk.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does WONK mean?
WONK noun- An overly studious person, particularly student.
- (by extension) A policy wonk or other intellectual expert.