In cryptography it is called a digest. A cryptographically strong digest doesn't allow to get source text based on the digest value without some additional knowledge. A digest value is the same for the same text, so you can calculate digest of the text and compare it with a published digest. A popular application is the password verification, so you can save digest instead of the password. This is of course prone to a dictionary attack which you already explored, and that is why it is strongly recommended to not use dictionary words for passwords.
