Typical claim by a geek? Not half! (7)
I believe the answer is:
average
'typical' is the definition.
(I've seen this before)
'claim by a geek? not half' is the wordplay.
'claim by' becomes 'aver' (aver means to state or claim something. I am not sure about the 'by' bit.).
'not half' indicates taking half.
'geek' with half the letters taken is 'ge'.
'aver'+'a'+'ge'='AVERAGE'
Can you help me to learn more?
(Other definitions for average that I've seen before include "Run of the mill" , "Mean - typical" , "About normal or usual" , "Mean figure?" , "Mean - everyday" .)