For North Vietnam or South Vietnam? The North Vietnamese were known simply as the 'North Vietnamese Army' (NVA) to US forces, but their actual title was Vietnam Peoples' Army, as it common practice in Communist states. The South Vietnamese Army was referred to as the Army of the Republic of Vietnam (ARVN).
US Military newspaper: Stars & Stripes
ARVN=Army Republic of South Vietnam. NVA=North Vietnamese Army.
I think the answer you want may be ARVN (Army of the Republic of Vietnam). It is pronounced and sometimes spelled as "Arvin."
My name is Michael K. Allan and I served in the Australian Army in Vietnam as a grunt. Is there another Michael Allan?
Presuming you mean the government supported by the US: The Republic of South Vietnam.
SOUTH Vietnam was called the "REPUBLIC of South Vietnam." Everyone in those days just called North Vietnam...NORTH VIETNAM.
There was one soldier in the Army who received the Navy cross during the Vietnam conflict. His name is COL (retired) Kenneth Ledford Jr. In Vietnam, he was a First Lieutenant, and he was a medevac, or "dust off" pilot. After retiring from The military, he became a teacher, and an instructor for the JROTC program. I was fortunate enough to have him as a JROTC instructor while I was a student at Pontiac Central High School. - SGT Christopher Ramos, US Army.
Since the questioner obviously knows the man's correct rank & correct spelling of his name, then the questioner fairly well knows that this individual was hanged as a WWII war criminal.
Australians.
China
His name was Mohammad Ali.
Perhaps because of the service of Medal of Honor winner Captain Euripedes Rubio, US Army who was born on 1 March 1938 in Ponce and who was killed in action on 8 November 1966 in the Republic of Vietnam.