The antonyms for the word "hard-heartedness" are words that convey empathy, kindness, and compassion towards others. Some of the antonyms include kindness, compassion, sensitivity, understanding, empathy, sympathy, and warmth. These words represent human traits that show care and concern for others, rather than being cold and unfeeling. Kindness shows the quality of being considerate and benevolent towards others. Empathy represents the ability to understand and share the feelings of others. Compassion is the capacity to care for others who are suffering. These antonyms help to describe a person who has a heart that is soft, caring, and understanding towards others.