Just add "characterized by". So someone who's nihilistic would have destructive tendencies to himself and others, or in the case of my post, would have the view of the human life and morals as being worthy of destruction. Notice also I didn't use the exact dictionary definition, but a general sense of what the word means in normal usage. The point being I was not referring to the name of the philosophy, the tenets of which I'm not particularly familiar with.