inhumanity
Extremely cruel behavior that ignores others’ feelings and suffering.
Inhumanity means cruel, brutal behavior that treats people as if they don't matter or don't deserve basic dignity and respect. When someone acts with inhumanity, they ignore the suffering they cause and treat others in ways that seem cold, heartless, or savage.
History is sadly full of examples where groups of people showed inhumanity toward others: slavery, genocide, and torture all represent inhumanity at its worst. But inhumanity can appear in smaller, everyday situations too. When students gang up to bully a classmate day after day without caring how much pain they cause, that's a form of inhumanity. When someone sees another person in trouble and deliberately walks away without helping, that can also be inhumanity.
Humanity refers both to all human beings and to the qualities that make us human: compassion, kindness, and empathy. So inhumanity describes behavior so cruel it seems to lack these basic human qualities.
The opposite of inhumanity is compassion and mercy. When people recognize the humanity in others and treat them with respect and care, even in difficult circumstances, they are rejecting inhumanity and choosing something better.