imbecilic       
adjective uk/ˌɪm.bəˈsɪl.ɪk/ us/ˌɪm.bəˈsɪl.ɪk/ (also imbecile)
 十分愚蠢的;弱智的
extremely stupid
  That was an imbecilic thing to do! 那件事做得太蠢了! 
 She looked at me with an imbecilic grin. 她带着愚蠢的笑容看着我。 
 See: imbecile
 - More examples
 - It's a staggeringly imbecilic approach to a serious subject.
 - He regards the government’s policy as imbecilic.
 - The rule is absurd and imbecilic.