This is the 5262nd most frequent Chinese word.
世友
"世友" means "lifelong friend" or "worldly friend."
In this sentence, "世友" is used as a proper noun referring to a person's name, illustrating its usage in direct reference to an individual.
世友是我最好的朋友。
Shiyou is my best friend.
Here, "世友" is used as a name to symbolize the rarity and value of a genuine friend in comparison to changing circumstances in life.
虽然世事多变，但真心的朋友像世友一样难得。
Although worldly affairs are ever-changing, true friends like Shiyou are rare.
In this sentence, "世友" metaphorically represents lifelong friends or companions, using it symbolically to emphasize the importance of such relationships.