Ukraine
noun: Ukrainian(s)
adjective: Ukrainian
United Arab Emirates
noun: Emirati(s)
adjective: Emirati
United Kingdom
noun: Briton(s), British (collective plural)
adjective: British
United States
noun: American(s)
adjective: American
Uruguay
noun: Uruguayan(s)
adjective: Uruguayan
Uzbekistan
noun: Uzbek(s)
adjective: Uzbek
Vanuatu
noun: Ni-Vanuatu (singular and plural)
adjective: Ni-Vanuatu
Venezuela
noun: Venezuelan(s)
adjective: Venezuelan
Vietnam
noun: Vietnamese (singular and plural)
adjective: Vietnamese
Virgin Islands
noun: Virgin Islander(s)
adjective: Virgin Islander