This is the 2553rd most frequent Japanese word.
天然
"天然" means "natural" or "unaffected."
'天然' refers to something occurring naturally, without human intervention. Here, it describes beauty that seems unaltered or spontaneous.
彼女は天然の美しさを持っています。
She has natural beauty.
'天然' is used to indicate that the water comes from a natural source and is unprocessed, emphasizing its purity.
この水は天然水です。
This water is natural spring water.
'天然' colloquially describes a personality trait that appears natural, often implying innocence or a lack of pretense.