Lighthearted (adjective)

1. Not serious or heavy-hearted; carefree.
2. Not burdened with worries or troubles.

Origin:

Early 17c., from light (adj.) + hearted.

Examples:

1. The party was lighthearted and full of laughter.
2. She was lighthearted and happy despite her problems.
3. He had a lighthearted attitude towards life.
4. The movie was a lighthearted romantic comedy.
5. He felt lighthearted after getting a good night's sleep.