Definitions for "Dissonant"
Sounding harshly; discordant; unharmonious.
The notes sound like they do not belong together.
Not consonant. Historically, the dissonant intervals are seconds, augmented fourth/diminished fifth, sevenths, and the compounds of these.
not musical in nature; "the unmusical cry of the bluejay"
characterized by musical dissonance; harmonically unresolved
Disagreeing; incongruous; discrepant, -- with from or to.
Keywords:  harmony, lacking
lacking in harmony
a relative term that means that the frequencies of two or more pitches do not "fit together".