A person who makes merry or enjoys festivities; a celebrant.

खुशियाँ मनाने वाला व्यक्ति

English Usage: The merrymaker at the party ensured everyone had a great time.

Hindi Usage: पार्टी में खुशियाँ मनाने वाला व्यक्ति ने सबका मज़ा कराया।