noun which may take the genitive case particle 'no', taru-adjective, adverb taking the 'to' particle
still and full of water; quiet and unmoving
Rare literary word describing water that is deep, still, and brimming, or by extension a state of profound quiet and stillness. Used in classical or poetic contexts.
湖面は湛然として、まるで鏡のようだった。
The lake surface was still and full, just like a mirror.
彼の心は湛然と静まり返っていた。
His mind was quiet and unmoving.