1.Definition: existing in fancy only
"Fantastic figures with bulbous heads the circumference of a bushel"
2.Definition: extraordinarily good or great; used especially as intensifiers
"A fantastic trip to the Orient", "The film was fantastic!"
3.Definition: extravagantly fanciful in design, construction, appearance
"Gaudi's fantastic architecture"
4.Definition: fanciful and unrealistic; foolish
"A fantastic idea of his own importance"
5.Definition: ludicrously odd
"Fantastic Halloween costumes"