/ Thesaurus / S Synonyms of south vietnam Find synonyms for: Noun1. South Vietnamusage: a former country in southeastern Asia that existed from 1954 (after the defeat of the French at Dien Bien Phu) until 1975 when it was defeated and annexed by North VietnamWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: labyrinth Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language