State Of Enjoyment
Joyful State
adjective, adverb, noun
You're so glad, you get glad again. No matter what you're doing, it's undoubtedly in a state of enjoyment.
嬉々 itself refers to a joyful state where someone happily does something. It's generally used as the adverb 嬉々として, which means “happily” or “gladly.” While less common, it can also serve as an adjective when combined with たる.
This word uses on'yomi readings of the kanji you learned... twice! You should be able to read this on your own.
子供ができればすぐ、嬉々として報告してくれるだろう。
As soon as they get pregnant, they will happily let us know.
父は、久しぶりに旧友に会い、嬉々として近況を語り合った。
My father saw his old friend for the first time in a long time and they happily caught up with each other.
コウイチが無事に帰ってきて、村には嬉々たる声が響いた。
Koichi returned safely and the village was filled with joyful voices.