idealist

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++i·deal·ist /aɪˈdɪəlɪst/ noun [countable]  BELIEVEsomeone who tries to live according to high standards or principles, especially in a way that is not practical or possible 理想主义者；空想家 → realist

Examples from the Corpus

idealist• Cavalier, arrogant, mendacious, and whatever else he was, Mike Straus was also an idealist.• Bazarov is an idealist and a brave man, and his aims are rational.• But at heart he remained an idealist about social issues.• By bribery - all men are corruptible - and by removing permanently any so-called idealists who stand in our way.• Paine, like many idealists in a hurry, was probably impatient of the slowness of legal remedies for existing abuses.• Gatting, the street fighter; and Gower, the idealist.

i·deal·ist nounChineseSyllable  

or someone Corpus tries standards live according high to who to

idealist
i‧deal‧ist /aɪˈdɪələst, aɪˈdɪəlɪst/ noun [countable]
someone who tries to live according to high standards or principles, especially in a way that is not practical or possible ⇨ realist