Synonyms for Visionary (same or very similar meaning)
WordNet sense 1 (a person with unusual powers of foresight):
illusionist, seer, seerWordNet sense 2 (not practical or realizable; speculative):
airy, impractical, windy, laputanWordNet sense 3 (characterized by or aspiring to impracticable perfection):
utopianFrom the ODE community, based on WordNetadd/edit