visionary

(noun) a person given to fanciful speculations and enthusiasms with little regard for what is actually possible.

(noun) a person with unusual powers of foresight. Synonyms: illusionist, seer.

(adj) not practical or realizable; speculative. Synonyms: airy, impractical, Laputan, windy. Examples: "Airy theories about socioeconomic improvement." "Visionary schemes for getting rich."