This is the 13578th most frequent Russian word.
нда
"Нда" is an informal exclamation expressing agreement, resignation, or reflection, similar to "well, yeah" or "hmm" in English.
Нда is used here as an interjection to express realization or acknowledgment.
Нда, похоже, мы опоздали.
Well, it seems we are late.
Нда is used here as a colloquial affirmation.
Он сказал «нда» и кивнул.
He said 'yep' and nodded.
Нда уж is used here as a phrase emphasizing agreement or confirmation.