Han-gook is the official name of the country commonly known as South Korea. However, there are several synonyms that can be used to refer to this nation. One common synonym is the Republic of Korea, which is the official name of the country. Another synonym is Hanguk, which is the Korean word for South Korea. Additionally, the term Korean Peninsula can be used to refer to the landmass that includes both North and South Korea. Finally, the abbreviation ROK or RoK can be used as a shorthand for the Republic of Korea. Overall, there are several alternatives to using the term Han-gook when referring to this fascinating nation.