utopian (adj.)

1550s, with reference to More's fictional country; 1610s as "extravagantly ideal, impossibly visionary," from utopia + -an. As a noun meaning "visionary idealist" it is recorded by 1832 (also in this sense was utopiast, 1845). Utopian socialism is from 1849, originally pejorative, in reference to the Paris uprising of 1848; also a dismissive term in communist jargon, in reference to the ideas of Fourier, St. Simon, and Owen, "the pre-scientific and infantile stage" of modern, practical socialism.