wisenheimer
/ˈwaɪzənˌhaɪmə(r)/noun
- US informal a person who behaves in an irritatingly smug or arrogant fashion, typically by making clever remarks and displaying their knowledge〈美, 非正式〉（尤指说俏皮话, 卖弄学识的）自作聪明的人。
词源
early 20th cent.: from WISE+ the suffix -(n)heimer found in surnames such as Oppenheimer.