1. [n]  an idealistic (but usually impractical) social reformer; "a Utopian believes in the ultimate perfectibility of man"
2. [adj]  being the best possible; characterized by ideal perfection; "the dim utopian future"; "utopian idealists"; "recognized the utopian nature of his hopes"
3. [adj]  pertaining to or resembling Utopia; "a Utopian novel"

UTOPIAN is a 7 letter word that starts with U.

1. \U*to"pi*an\, a.
   Of or pertaining to Utopia; resembling Utopia; hence, ideal;
   chimerical; fanciful; founded upon, or involving, imaginary
   perfections; as, Utopian projects; Utopian happiness.
   
   

2. \U*to"pi*an\, n.
   An inhabitant of Utopia; hence, one who believes in the
   perfectibility of human society; a visionary; an idealist; an
   optimist. --Hooker.