Very numb (4)
I believe the answer is:
dead
This clue is a double definition.
'very' is the first definition.
(dead can mean very or absolutely, eg 'dead wrong')
'numb' is the second definition.
(eg a dead arm)
(Other definitions for dead that I've seen before include "Lifeless" , "no longer with us" , "Lookalike" , "directly" , "Late; exact" .)