Nobody making two high-pitched sounds (9)
I believe the answer is:
pipsqueak
'nobody' is the definition.
(pipsqueak is a kind of nobody)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for pipsqueak that I've seen before include "Contemptible person" , "Whippersnapper" , "Insignificant person" , "Dwarf" , "Tiny person, worthy of contempt" .)