Undetectable by ear (9)
I believe the answer is:
inaudible
(Other definitions for inaudible that I've seen before include "Unable to be heard" , "Cannot be heard" , "Impossible to hear" , "Not aurally detectible" , "impossible to grasp" .)
I believe the answer is:
inaudible
(Other definitions for inaudible that I've seen before include "Unable to be heard" , "Cannot be heard" , "Impossible to hear" , "Not aurally detectible" , "impossible to grasp" .)