Completely insensitive (4)
I believe the answer is:
dead
I believe this is a double definition.
'completely' is the first definition.
('dead' can be a synonym of 'completely')
'insensitive' is the second definition.
(thesaurus)
(Other definitions for dead that I've seen before include "cold" , "Lifeless" , "dull" , "Insensitive" , "Absolutely" .)