This is the 4798th most frequent Japanese word.
水谷
"水谷" (Mizutani) is a Japanese surname meaning "water valley."
Here, 水谷 is used as a proper noun, indicating a person's surname.
水谷さんは学生です。
Mr./Ms. Mizutani is a student.
In this sentence, 水谷 is used as the name of a person engaging in the activity of visiting a location.
水谷は山間部の麓に流れる清らかな川を見に行った。
Mizutani went to see the clear river that flows at the base of the mountains.
Here, 水谷 might metaphorically represent a picturesque place or could be referencing a well-known scenic location or person's name.