Безопасен ли wordthirst.com?

At first, I was excited about WORD THRIST, especially for the pictures that illustrate the definitions. I have several children I help home school, and it is very helpful with instructing them. However, I soon learned whenever I clicked a second or third time on a word, definition, or when I was right In a word quiz, and it urged me on to click again, I received a warning from my computer's "security" company {NORTON), informing me that going onto that site "was a known security risk". It did it ever time! Of course, I immediately backed out.