@Rarebear Sure, although I would definitely admit that it is really challenging to think of things that you can verify as genuinely inexplicable! I think such things are really rather rare, and I believe that the vast majority of things are unexplained, rather than inexplicable.
One example that springs to mind of something that might be inexplicable is trying to explain the mental state and motivations of someone who is no longer alive. Let’s say this dead person previously committed an unusual act with no clear or obvious motivational purpose, and then dies. Those left behind can offer suggestions and potentially correct explanations for that act, but as those explanations can never be verified as a result of the individual’s death, I would therefore say that it’s fair to define that behaviour as “inexplicable”, since said explanations can never be verified.
Of course, this example can get quite muddy, if you start to consider the extent to which individuals can accurately explain their own behaviours and mental states, and the extent to which we engage in post-hoc reasoning for our actions. Or, I suppose, you could argue that in the future, we may develop means to bring people back to life and therefore, the behaviour may cease to be inexplicable!