INDEC'OROUS, adjective [Latin indecorus; in and decor, decus, deceo, to become.] Unbecoming; violating good manners; contrary to the established rules of good breeding, or to the forms of respect which age and station require. It is indecorous in a young person to take the highest place in company, when his superiors are present. indecorous is sometimes equivalent to indecent; but it is less frequently applied to actions which offend modesty and chastity.