lacking in one's appreciation of music (not necessarily due to actually being tone deaf
I'm sorry but i just never payed much attention to music. I'm tone-deaf.
A person who thinks he/she can hit the right notes and stay in tune when they really sound horrible and are not good at all. They are often unable to hear the difference between two notes or on pitch notes and flat notes.
People on American Idol that audition that think they can sing but you hear them singing on tv horribly yet they dont realize they are horrible. These people are tone-deaf