How do i block access to horror sites?

[simsa]

Installed NN for first time a few days ago. Works great on blocking access to adult related sites ,or sites with reference to violent matters. But if i type in the name of any horror film it still brings up those sites which have disturbing images on them. If i block access to image/video then access is blocked to all including educational. How do i block access to horror film sites.
Thanks in advance!