Definitions of fantastic:

• adjective:   extraordinarily good; used especially as intensifiers

  Example: "A fantastic trip to the Orient"

• adjective:   exceedingly or unbelievably great

  Example: "The bomb did fantastic damage"

• adjective:   existing in fancy only

  Example: "Fantastic figures with bulbous heads the circumference of a bushel- Nathaniel Hawthorne"

• adjective:   extravagantly fanciful and unrealistic; foolish

  Example: "A fantastic idea of his own importance"

• adjective:   ludicrously odd

  Example: "Fantastic Halloween costumes"