Indecorous, a.
Etymology: [L. indecorous. See In- not, and Decorous.]
Not decorous; violating good manners; contrary to good breeding or etiquette; unbecoming; improper; out of place; as, indecorous conduct. It was useless and indecorous to attempt anything more by mere struggle. Burke.
Syn. -- Unbecoming; unseemly; unbefitting; rude; coarse; impolite; uncivil; ill-bred.
Shades of meaning
Fernald lists indecorous only as an antonym, under becoming.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given