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.
例句
Idealistic young people died for the cause...理想主义青年为这项事业而献身。Older mothers tend to be too idealistic about the pleasures of motherhood.较年长的母亲往往对身为人母的乐趣过于理想化。
英英词典释义
Adjective
1. of or relating to the philosophical doctrine of the reality of ideas
2. 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"