Definition of "bacchanalian"

With the help of a sleepy waiter, Little Billee got the bacchanalian into his room and lit his candle for him, and, disengaging himself from his maudlin embraces, left him to wallow in solitude.

1894, George du Maurier, “Part Third”, in Trilby: A Novel, New York, N.Y.: Harper & Brothers, page 165

Within three hours we'd drunk the place dry. Miraculously, we all made it back on the bus, but I've never seen a more bacchanalian scene of wanton debauchery than the ride back to the hotel.

2015, Adam Jones, Bomb: My Autobiography