The Númenóreans (Ad.Adûnai) were the men of Númenór, those descendants of the three houses of the Edain who had settled the Island Realm of Númenór in the second Age.Those Númenóreans of the Elendili who settled the coasts of the Westlands and founded the kingdoms of Arnor and Gondor were also known as the Dúnedain and they continued to speak Sindarin as their formal speech of etiquette although they used Adûnaic as their lingua franca, and later its descendant Westron.The King's Men or Aruwanai who settled the coastlands south of Umbar were called Black Númenóreans by their northern brethren
The Adûnai regarded the pale skin of the Eldar as prestigious, however many among the hard working rural population and the sun-tanned mariners had ruddy or darker skin, so pale skin became the ideal of the upper classes. In later times it was was seen as a symbol of pure-blooded númenórean descend, as the former free working classes rose to the status of urban citizens and the lower classes were replaced by unfree slaves imported from all over Middle-Earth and a mixed-blooded class of unfree and semi-unfree freedmen evolved. The original Adûnai were a tall folk, 6 feet, 4 inches being not uncommon among them, although their later descendants used to be smaller in statue. Most common Adûnai were black or brown haired, being largely descendants of the Beorians and Halethrim, but in the royal line there also were some flaxen or golden-haired families, offspring of the house of Hador. Adûnai were usually grey-eyed, though brown or blue eyes were not uncommon.
The Adûnai revered the One-god Êru and his subject-spirits the Avalôi or Êru-bêni, especially Gimilnitîr or Avradî and Amân or Adûnakhôr, but also Abâr, Agân, Azâr and Magân.Later under Zigurûn's tutelage they largely abolished the reverence of Êru and made the cult of Alkar or Mulkhêr their imperial religion, the few remaining faithful or Elendili mostly left Númenór for the colonies of the northwest.
The Adûnai were the greatest Seamen and Scholars among the mortals and certainly also the most skilled artificians and warriors.However with the drowning of Númenór much of the Adûnai's knowledge was lost forever and their Dúnadan and Aruwanai descendants only inherited a shadow of their forefathers' former glory.
While the early half-elven royal line of the númenórean Kings lived up to 400 years and even the lesser Númenoreans often lived up to 200 years, their Elendili and Aruwanai descendants of the late third age only came to live for no longer than 100 years, 150 years being a sign of royal descent, with the notable exception of Elessar I who died at the age of 210.