Inharmonious, a.
Etymology: [Pref. in- not + harmonious: cf. F. inharmonieux.]
1. Not harmonious; unmusical; discordant; dissonant. Sounds inharmonious in themselves and harsh. Cowper.
2. Conflicting; jarring; not in harmony.
Shades of meaning
Fernald has no entry of its own for inharmonious; he lists it under incongruous.
Where he writes about it:
Two or more things that do not fit well together, or are not adapted to each other, are said to be incongruous; a thing is said to be incongruous that is not adapted to the time, place, or occasion; the term is also applied to a thing made up of ill-assorted parts or inharmonious elements. — from incongruous
Discordant is applied to all things that jar in association like musical notes that are not in accord; inharmonious has the same original sense, but is a milder term. — from incongruous