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.
理想主义的年轻人为这项事业而献身。
an over-simplistic and idealistic vision of family dynamics.
一种对家庭动力学的过于简单和理想主义的看法。