As a Verb or Adjective: 1. To not be aware of something or conscious of what is happening around you. English = (be) oblivious, (be) unaware. 2. To have no knowledge, understanding or ability. English = (be) clueless. 3. To have a look or expression which suggests that you do not understand something or that you are not very intelligent. English = (be) vacant, have a vacant look.