Unable to perceive musical pitch accurately (4-4)
I believe the answer is:
tone-deaf
'unable to perceive musical pitch accurately' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tone-deaf that I've seen before include "Without musical appreciation" , "Unable to perceive musical pitch accurately" , "Not able to distinguish pitches" , "Unable to distinguish differences in musical pitch" , "Unable to distinguish variations in musical pitch" .)