taru-adjective, adverb taking the 'to' particle
wide and deep; voluminous
Literary or poetic description of a body of water that is both broad and deep, or figuratively of something vast and abundant. Often used in classical or formal contexts.
汪々たる大海原を前に、彼は言葉を失った。
Before the vast, deep ocean, he was at a loss for words.
その湖は汪々として、底が見えないほどだった。
The lake was wide and deep, so much so that the bottom could not be seen.
深々 emphasizes depth, often used for snow or night, while 汪々 combines width and depth, typically for water.
The kanji 汪 means 'deep and vast (of water)'. The reduplicated form 汪々 is a literary Chinese-derived expression used in classical Japanese to describe expansive, deep waters. The exact historical derivation is uncertain; it is a Sino-Japanese word.