WordWeb Online

1. Impressive because of unnecessary largeness or grandeur; used to show disapproval
    
2. Affectedly genteel; to carry an air of affected importance; to be snobbish and haughty
   "It might be a bit of an arty lifestyle, but it's not a grandiose, fashionable life";
   - hifalutin [informal], highfalutin [informal], highfaluting [informal], hoity-toity [informal], la-di-da [informal], lah-di-dah [informal], la-de-da [informal]

See also: impressive, pretentious

Encyclopedia: Grandiose