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."