This is the 1125th most frequent Japanese word.
もっとも
"Most", "extremely", or "quite."
In this sentence, '最も' is used as an adverb to indicate the superlative degree, meaning 'the most' or 'the best.'
彼は最も優れた選手です。
He is the best player.
Here, 'もっとも' functions as an adjective meaning 'reasonable' or 'justified,' often used to express agreement.
その提案はもっともだと思います。
I think that suggestion is reasonable.
In this case, 'もっとも' is used as a conjunction meaning 'however' or 'but,' introducing a contrasting explanation.