RichThesaurus
atonal
vs
unmellifluous
atonal
adj
Not tonal, lacking tones.
Lacking a tonal center or key.
unmellifluous
adj
Not mellifluous; harsh-sounding; dissonant.
How often have the words
atonal
and
unmellifluous
occurred in a corpus of books?
(source:
Google Ngram Viewer
)