Definition of “idealism” - Learner’s Dictionary

idealism

noun [ U ] us uk /aɪˈdɪəlɪzəm/

the belief that your ideals can be achieved, often when this does not seem likely to others

idealist noun [ C ]

a person who believes that it is possible to achieve your ideals

idealistic adjective us uk /aɪˌdɪəˈlɪstɪk/

(Definition of “idealism” from the Cambridge Learner's Dictionary © Cambridge University Press)