1. To teach someone, or a group of people, to behave in a way that is more gentle and polite: Ingrid's parents hoped that a boarding school might help civilize her so she wouldn't be so hateful.
2. To make more concerned, fair, and reasonable: Dr. Anderson is a new doctor who has been civilizing the treatment of patients with mental illnesses.
3. To guide or to help others to have a more highly organized and more modern way of living: The missionaries were convinced that it was their responsibility to civilize the natives in the African jungles so they could improve their conditions of existence.