To sound in a discordant way; to clash or be out of harmony with something.
From Latin dissonare (dis- 'apart' + sonare 'to sound'). This back-formation from dissonance is rarely used, as 'dissonant' as an adjective became the more common form.
While 'dissonate' is technically correct and means to clash, it almost never appears in modern English—people just say 'clash' or use 'dissonance' instead. This is a word that lost the evolution race.
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