1. Having detailed knowledge, and the skills to use it effectively
   "well-informed readers"; "The clued-up receptionist was surprisingly well-informed about company procedures";
   - intelligent, clued-up [Brit, informal], savvy [informal]
    
2. Up to date with the latest developments
   "She's always well-informed about current events";
   - clued-up [informal], in touch, plugged in [informal], switched on [informal]

See also: sophisticated