Stealth camping is parking within town limits in locations that are not likely to annoy anyone or result in parking fines. ie in Bergen recently, we parked right on the harbour where there are pay and park meters that were free overnight.
In Oz, our rig is technically a heavy vehicle that is not supposed to park on the street for more than an hour. The big-rigs club use ABC sites - Airports, B (can't remember what that stands for) and Cemeteries. Obviously industrial areas are a good bet also. Not always the best or most scenic spot, but close to big towns and cities, there isn't a lot of choice if you want to avoid caravan parks.
"bush camping" is probably close to your "wild camping". Often the term "free-camping" is used, but this is a bit ambiguous as not everyone interprets "free" in the same way..