(verb) To spoil or ruin (one's chance of success)
"Of all the animals, man is the only one that is cruel. He is the only one that inflicts pain for the pleasure of doing it."
"Man is the cruelest animal."
"Why is there ever this perverse cruelty in humankind, that makes us hurt most those we love best?"
"If you cannot love me, I will die. Before you came I wanted to die, I have told you many times. It is cruel to have made me want to live only to make my death more bloody"