As you can see this section needs some work, all contributions are helpful!
Airstrike: Term started in KW
Bobby: American Nickname for the Soviet BA-64 Light Armored Car used by the North Koreans
Bug-Out: A term used to describe the retreats of Green GIs along the Pusan Perimeter. They just panic and run when things got to hot.
Chopper: Term strted in KW
Hooch: Comes from the Japanese word "uchi." Means a hut.
Land of the Morning Calm: A Korean Name for Korea.
Mansei!: North Korean equivalent of the Japanese "Banzai!", the Zulu "Usuthu!", or the Rebel Yell. Screamed at many a GI during a charge.
MASH: mobile army surgical hospital
Rabbit, The: Look at the two Koreas on a map.
Rambling ROKs: Term bestowed on the 3rd ROK Division. One of the best units in the ROK Army.
Police Action: Truman's term for the war.
People's Volunteers: Chinese counter-propoganda to Truman's policemen.
Operation Yo-Yo: The Marines were originally shipped to Wosan from Inchon. The port was found to be full of mines and they were sent back. Then the port was thought safe and they were finally sent back. Finally landing on October 26th, 1950 ending Operation "Yo-Yo"
Fatherland Liberation War: North Korean name for the war. Obviously soviet inspired
Sources: Military History magazine, Conflict: Korea, and others