Humanitarianism is a way of behaving out of kindness to other people. Someone who is a humanitarian is a person who helps to improve the lives of other people without thinking about their race, belief or nationality.
Humanitarianism also means basic morality indispensable for human being. And there are international laws called "international humanitarian law" considered to created out of humanitarianism of this mean. Among them, Geneva Conventions on the matter made at the time of wars are well known.