Ambrym is a proper noun that refers to an island located in the Vanuatu archipelago in the South Pacific Ocean. Being a place name, there are no exact synonyms for it. However, one can use some alternative words that come close to describing the island. For example, Vanuatu is the name of the country where Ambrym is located. Additionally, Vanuatu is part of the Melanesia region, an area comprising islands scattered around the Pacific Ocean. Therefore, one can say Ambrym is part of Melanesia or located in the South Pacific. In summary, although there are no direct synonyms, one can use related words to describe Ambrym's location.