Merriam-Webster Collegiate Dictionary - imaginary

 adjective  Date: 14th century  1.  a. existing only in imagination ; lacking factual reality  b. formed or characterized imaginatively or arbitrarily his canvases, chiefly ~, somber landscapes — Current Biography  2. containing or relating to the ~ unit ~ roots  • imaginarily adverb  • imaginariness noun Synonyms:  ~, fanciful, visionary, fantastic, chimerical, quixotic mean unreal or unbelievable. ~ applies to something which is fictitious and purely the product of one's imagination an ~ desert isle. fanciful suggests the free play of the imagination a teller of fanciful stories. visionary stresses impracticality or incapability of realization visionary schemes. fantastic implies incredibility or strangeness beyond belief a fantastic world inhabited by monsters. chimerical combines the implication of visionary and fantastic chimerical dreams of future progress. quixotic implies a devotion to romantic or chivalrous ideals unrestrained by ordinary prudence and common sense a quixotic crusade.