As a Noun: 1. In children, bad or disobedient behaviour. English = naughtiness. 2. In adults, risque or slightly rude, sexually suggestive or even indecent language or behaviour. As a Verb or Adjective: 1. Of children, to behave badly or in a disobedient way. English = (be) naughty. 2. Of adults, or books and pictures, to be slightly rude or indecent. English = (be) naughty, (be) risque. Idiomatic English = (be) dirty, (be) cheeky. 3. To tell a child that they have behaved badly or in a disobedient way. English = chastise. Interactive: 1. Used alone to tell someone (especially a fellow adult in a joking way) that they have been naughty or risque.