Scientist: "Working Si chips totally gutted" (9)
I believe the answer is:
physicist
'scientist' is the definition.
(I know that physicist is a type of scientist)
'working si chips totally gutted' is the wordplay.
'working' indicates an anagram.
'gutted' suggests removing the centre (to gut something is to remove its insides).
'totally' with its middle taken out is 'ty'.
'si'+'chips'+'ty'='sichipsty'
'sichipsty' is an anagram of 'PHYSICIST'.
(Other definitions for physicist that I've seen before include "Expert in the science of matter and energy" , "To become a scientist, doctor gets a name change to the street" , "One studying the nature of matter" .)