Longman Dictionary of Contemporary English
Wiktionary
a. 1 Unable to clearly distinguish the difference in pitch between different notes. 2 (context colloquial English) Having little appreciation of music, whether or not as a result of (1).
WordNet
adj. unable to appreciate music
Usage examples of "tone-deaf".
Those damn dirges are still running around my brain, like a tone-deaf rat with a megaphone is trapped inside my head.
Any Lizard monitoring this one, though, would have to be extraordinarily tone-deaf to miss the obvious fact that Penny was lying through her teeth.
Apparently, the Chief, despite his passion for popular music, was tone-deaf.
The band, mercifully silent, enthusiastically quaffed beer presented them by some tone-deaf customer.
Somewhere within earshot of the drawing-room a string orchestra was playing, but luckily in a subdued manner, so that Hornblower was spared much of the irritation that he usually suffered when he was compelled to listen to music with his tone-deaf ear.