Good question. You can make it more difficult for people but there's really not a way to stop someone who is computer savvy and has the right software. If the text is not important for SEO, reasons, you can save it as an image and import it like an ordinary picture. However even this is not 100 % fool-proof as ICR software is pretty widespread and the image can be copied into this software and converted to editable text.
Aha! And I was thinking you would someday be taken bodily into heaven. As one who got into computers when Mayflower at the Corporation had an IBM main frame with 16K of RAM (1966) I couldn't find but one way. Don't put stuff on the internet.