Synonyms:
fanciful, notional
Meaning: indulging in or influenced by fancy; "a fanciful mind"; "all the notional vagaries of childhood"
Usage examples
Those which failed seem to us now fanciful, those which succeeded appear to us sublime.
Those who have read the third lecture in Part I. will remember the speculation in which Kepler indulged respecting the arrangements of the planets, the order in which they succeeded one another in space, and the law of their respective distances from the sun; and his fanciful guess about the five regular solids inscribed and circumscribed about their orbits.