If you’re creative enough you can create names that are offensive but not currently on the banned list. They append it every so often.
Someone found it tasteless and Blizzard agreed it wasn’t appropriate. It takes more than one report to get a forced name change.
I’d know, friend of mine was concerned his name wasn’t appropriate (mostly due to joining a very family friendly guild) and asked the guildies to report it. It took a few days before it kicked in.