undecorated Syllabification: (un·dec·o·rat·ed)Pronunciation: /ˌənˈdekəˌrātid/Definition of undecorated adjective 1not adorned or decorated:the walls were completely undecorated 2(of a member of the armed forces) not honored with an award. undecorated in other Oxford dictionaries Definition of undecorated in the British & World English dictionary