adj. 25B6; adjective
harmonious music : TUNEFUL, melodious, melodic, sweet-sounding, mellifluous, dulcet, lyrical; euphonious, euphonic, harmonic, polyphonic; informal easy on the ear.
their harmonious relationship : FRIENDLY, amicable, cordial, amiable, congenial, easy, peaceful, peaceable, cooperative; compatible, sympathetic, united, attuned, in harmony, in rapport, in tune, in accord, of one mind, seeing eye to eye.
a harmonious blend of traditional and modern : CONGRUOUS, coordinated, balanced, in proportion, compatible, well matched, well balanced.
discordant, hostile, incongruous.