Being courteous means showing politeness, respect, and consideration towards others. It is an essential part of personal etiquette that helps build positive human relationships. Synonyms for "be courteous to" include "treat kindly," "show civility," "display good manners," "exhibit graciousness," "be polite," "act chivalrously," "demonstrate decorum," "manifest cordiality," "illustrate gentle behavior," and "express respect." These synonyms convey the same meaning but with different nuances. Using various synonyms for "be courteous to" will result in more precise and diverse language use, allowing for more effective communication and better relationship-building with others.