{s} of or pertaining to idealists, principled, living according to some standard of perfection; of or pertaining to idealism, of the tendency to form ideals, of the pursuit of high and noble goals
of high moral or intellectual value; elevated in nature or style; "an exalted ideal"; "argue in terms of high-flown ideals"- Oliver Franks; "a noble and lofty concept"
If you describe someone as idealistic, you mean that they have ideals, and base their behaviour on these ideals, even though this may be impractical. Idealistic young people died for the cause. believing that you should live according to high standards and principles, even if they cannot really be achieved, or showing this belief realistic