Prior to VS2013 you could use:
[System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)]
so that it doesn’t show up in IntelliSense. If the consumer still wants to use it they can, but it won’t be as discoverable.
Keith’s point about over-engineering still stands though.
Since VS2013 this feature has been removed. As noted in https://github.com/dotnet/roslyn/issues/37478 this was “by design” and apparently will not be brought back.