Let's learn the Korean word "군침." 

"Let's take a closer look at the Korean word "gunchim." We will also study the meaning of "gun" in "gunchim" and words that contain "군(Gun)."
"Gunchim is a derived word formed by combining a prefix with the stem of a word or the root word."
"In Gunchim, "Gun" is a prefix that adds the meaning of "useless" or "unnecessary."
군침(Gunchim) is the saliva that accumulates in the mouth when someone thinks about or sees something delicious. It is often used figuratively to describe something tempting or desirable.
Example sentences:
2:15 군침
More words begin with the prefix "Gun" used in "Gumchim."
6:30 군말, 군살, 군걱정, 군더더기
Words begin with the prefix "Gun" but it is a shortened form of the adjective "guneun" derived from the verb "to grill."
8:28 군밤, 군고구마, 군감자, 군옥수수