As a Verb or Adjective: 1. To be unpleasant, harmful, undesirable, or to be of an unacceptable quality, amount or standard. English = (be) bad. Interactive: 1. Used alone to express your feelings that something you have been told is harmful, undesirable, or of an unacceptable quality. English = 'How dreadful!', 'Oh no, that's awful!' and so on.