stolid
adjective disapproving uk/ˈstɒl.ɪd/ us/ˈstɑː.lɪd/
(人)不动感情的,淡漠的,无动于衷的;(事物)索然无趣的
(of a person) calm and not showing emotion or excitement, or (of a thing) not interesting or attractive
He's a very stolid, serious man. 他是个喜怒不形于色、很严肃的人。
The college is a stolid-looking building with no lawn. 这所学院外观呆板,连草坪都没有。