stu·pid / ˈst(y)oōpid/ • adj. (-pid·er, -pid·est) lacking intelligence or common sense: I was stupid enough to think she was perfect. ∎ dazed and unable to think clearly: apprehension was numbing her brain and making her stupid. ∎ inf. used to express exasperation or boredom: she told him to stop messing with his stupid painting.• n. inf. a stupid person (often used as a term of address): you're not a coward, stupid!DERIVATIVES: stu·pid·i·ty / st(y)oōˈpiditē/ n.stu·pid·ly adv.