If you haven't read 1984, this is really confusing, but a "memory hole" is a hole into which you place something you don't want to have any memory of, destroying it forever. The ironic name is an example of "doublethink."
And those who've actually read it also know that Newspeak is also a term he coined and that since we don't actually
have newspeak, the natural extrapolation of the term Doublethink into a spoken application is the term Doublespeak....
Right?