See how-to-enforce-a-dns-filtering-service for details.
For example, to block all pages that contain the word “pizza”:
pluck + flee word pizza
See flee for more information.
You can also try using a large flee host list.
pluck + safe
See safe for more information.
As a warning, the lists are neither perfect nor comprehensive.
A flee-host list will in general be more effective than a block-host list.
TODO: fill me in.
You can use all of the options above at once if you like.