When you're idealistic, you dream of perfection, whether in yourself or other people. For example, you might have the idealistic goal of bringing an end to childhood poverty in the world.
The adjective idealistic describes someone whose plans or goals of helping others are lofty, grand, and possibly unrealistic. Do you think world peace is within reach? You're idealistic. If your vision of the world is idealistic, you believe all problems can be solved and that all people can reach their full potential. Idealistic comes from the Greek idea, or "ideal prototype."