Definition of "Fantastic" :

adjective: ludicrously odd

"Fantastic Halloween costumes."

adjective: extraordinarily good or great; used especially as intensifiers

"A fantastic trip to the Orient."

adjective: extravagantly fanciful in design, construction, appearance

"Gaudi's fantastic architecture."

adjective: existing in fancy only

"Fantastic figures with bulbous heads the circumference of a bushel."

adjective: fanciful and unrealistic; foolish

"A fantastic idea of his own importance."