老词 Old word：
一（yī）one
望（wàng）see at a far distance
无（wú）no, do not have
际（jì）borderline
一望无际：一眼望不到边，形容非常辽阔（liáokuò. Vast, broad）。
You take one look and cannot see the end of sth. It is used to describe extremely broad.
例句：一望无际的大草原里有着一群（qún. Measure word for a group of living things）群吃草的牛羊。
Example: There are groups of grass-eating cows and sheep on the prairie which is so big you cannot see the end.
新用 New use：
“际”代指了发际线（fàjìxiàn. Hairline）。一眼看过去看不到发际线，用于形容掉发（diàofà. Drop hair, lose hair）多，多由生活压力造成。
“jì” is used to refer to the hairline. When you take one look and cannot see the hairline, indicating someone has lost a lot of hair, mostly due to stress in life.
例句：期末考试要复习的东西太多了！我马上就有过上一望无际的日子了。
Example: There are so much to revise for finals! I will soon be living the life of “retreating hairline”.