Unable to be seen (9)

I believe the answer is:
invisible
(Other definitions for invisible that I've seen before include "Not able to be seen" , "Hidden - imperceptible" , "Impossible to see" , "Out of sight" , "Blind" .)
I believe the answer is:
invisible
(Other definitions for invisible that I've seen before include "Not able to be seen" , "Hidden - imperceptible" , "Impossible to see" , "Out of sight" , "Blind" .)