I agree the second example is more understandable, but I think most of that benefit comes from named parameters (a language feature), not the naming convention itself. That is, were the naming up to me, I would prefer:

  NSString *filtered = [unfiltered replace:@"verbose"
                                   with:@"explicit"
                                   options:CaseInsensitive
                                   range:Range(0, [unfiltered length])];

Of course, I'm making assumptions about what those parameters mean. But I find this much more clear, assuming the intentions are what I think they are.