Every time a password is entered if it IS on the list, it's not considered secure, so by default, if the password you try is NOT on the list, it was considered "secure "

I understood that is what you intended, but the result is that you are saying "test_123" was considered secure. If you want to develop it into a serious service, I would advise against telling someone if a password is secure or not. Simply say something like "The password was/wasn't found in our database" or whatever.

The link I clicked was on Reddit. I'm talking about a disclaimer on the site. Hiding the disclaimer in "About" is, to me, shady practice. Not accusing you of doing it maliciously, but it certainly feels shady when the most important disclaimer - this site harvests the input - is hidden from the input field. If anything it should be reversed: you see the disclaimer, and click a button to reach the input.

Not trying to be short with you, or belittle your project, but anything related to password security needs approached with the utmost scrutiny. I highly suggest you read about how Troy Hunt deals with this exact problem (user entering a password and checking against a db of known-breached passwords) with k-anonymity.

You can find the link here.