adverb taking the 'to' particle, taru-adjective
delighted; overjoyed
Archaic literary word describing a state of great delight or joy. Used with と or in たる form, often in classical or highly formal contexts.
彼は吉報を聞いて歓然とした面持ちで部屋を出た。
He left the room with a delighted expression upon hearing the good news.