thoái
Thoái is a Vietnamese Sino-Vietnamese morpheme derived from the Chinese character 退, meaning retreat, withdraw, or regress. In contemporary Vietnamese it is mainly used as a bound morpheme in compound terms rather than as a stand‑alone verb in everyday speech. Its core sense is retreat or decline, applied across domains such as politics, medicine, and general description of deterioration.
In usage, thoái appears most often in established terms. Common examples include thoái hóa, which denotes degeneration
As a standalone word, thoái is relatively rare in modern ordinary language and tends to be found