Most iron-hearted is often associated with negative traits like indifference, cruelty, and ruthlessness. Its antonyms, on the other hand, are terms that convey compassion, empathy, kindness, and warmth. The opposite of iron-hearted is soft-hearted or tender-hearted, both of which highlight a person's sensitivity and kindness. Other antonyms include sympathetic, thoughtful, and merciful, which all connote a person's capacity for understanding and caring about others' feelings. Moreover, some antonyms of iron-hearted are affectionate, compassionate, and considerate, which indicate a person's ability to show love and tenderness towards others. In summary, antonyms for most iron-hearted revolve around positive traits like empathy, kindness, understanding, and love.