A person skilled with computers essentially protected thief (6)
I believe the answer is:
techie
'a person skilled with computers' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'essentially protected thief' is the wordplay.
'essentially' indicates the central letters.
'thief' becomes 'hie' (I am not sure about this - if you are sure you should believe this answer much more).
The centre of 'protected' is 'tec'.
'tec'+'hie'='TECHIE'
Can you help me to learn more?
(Other definitions for techie that I've seen before include "PC expert" , "computer expert" , "Expert in some practical science" , "IT whizz" .)