The antonyms for the word "heavy-hearted" are "light-hearted," "happy," "joyful," "gleeful," "upbeat," and "cheerful." If you are feeling light-hearted, it means you are carefree, lighthearted, and carefree. Being happy means you are content, gratified, and pleased. Joyful, on the other hand, means delight or rejoicing in triumph, and gleeful connotes bursting with joy. Being upbeat means having a positive attitude, and feeling cheerful means being in good spirits. Using antonyms is an effective way to express different moods and emotions, and they can be used to create a more nuanced and vibrant language.