I'm aware of this question:
Over there it's suggested that blatantly off-topic questions are closed by entering a custom close reason. I can see the benefits of that as new users will get a bit more guidance why their question isn't a good fit for the site.
Nevertheless, it would be useful to have a built-in 'blatantly off-topic' reason as well. One use case would be when there are already enough comments explaining why a question is off-topic. In such cases, adding an extra comment when voting to close might be repetitive (or even unfriendly if well-meaning users are forced to repeat criticisms that were already mentioned).
As an example, I came across this question in the close vote queue. One user already left a comment explaining why the question probably isn't a good fit for the site. When casting my close vote, I could either add a custom reason or go with the existing close reason (which was 'needs details or clarity'). In this case, I think a blatantly off-topic close reason would be useful to have.
For example, on Travel there's a simple reason:
Blatantly off-topic This question has nothing to do with traveling.
On Politics, the reason is a more circular catch all ('it's off-topic because it doesn't fit our scope'):
This question does not appear to be about governments, policies and political processes within the scope defined in the help center.
So what do you think? Should we have a broader catch-all close reason? And if so, how should it be phrased?