Leave egghead inside in peace (5)
I believe the answer is:
quiet
'peace' is the definition.
(thesaurus)
'leave egghead inside in' is the wordplay.
'leave' becomes 'quit' (quitting is a kind of leaving).
'egghead inside' becomes 'e' (I am not sure about this - if you are sure you should believe this answer much more).
'in' is an insertion indicator.
'quit' going around 'e' is 'QUIET'.
Can you help me to learn more?
(Other definitions for quiet that I've seen before include "Still" , "Tranquil, calm" , "Hush" , "Without sound" , "Absence of noise" .)