fantast
noun
[ ˈfantast ]
• an impractical, impulsive person; a dreamer.
• "the accusation was passed to the national press from the mouths of liars and fantasts"
Origin:
late 16th century (formerly also as phantast ): originally via medieval Latin from Greek phantastēs ‘boaster’, from phantazein or phantazesthai (see fantastic); in modern use from German Phantast .