The word "un-idealistic" suggests a lack of idealism; therefore, its antonyms would be words that convey idealism. Some antonyms for un-idealistic could include words like optimistic, hopeful, principled, ethical, visionary, ideal, or romantic. These words suggest a belief in the possibility of creating a better world and a commitment to ethical principles. To be idealistic is to see the world not as it is but as it could be, with a focus on growth, improvement, and progress. Antonyms for un-idealistic can be used to describe people who are driven by a sense of purpose and a commitment to create positive change.