emphasis If you say that something is fantastic, you are emphasizing that you think it is very good or that you like it a lot. I have a fantastic social life I thought she was fantastic. = great
You describe something as fantastic or fantastical when it seems strange and wonderful or unlikely. Unlikely and fantastic legends grew up around a great many figures, both real and fictitious The book has many fantastical aspects
extraordinarily good; used especially as intensifiers; "a fantastic trip to the Orient"; "the film was fantastic!"; "a howling success"; "a marvelous collection of rare books"; "had a rattling conversation about politics"; "a tremendous achievement"
ludicrously odd; "Hamlet's assumed antic disposition"; "fantastic Halloween costumes"; "a grotesque reflection in the mirror"
exceedingly or unbelievably great; "the bomb did fantastic damage"; "Samson is supposed to have had fantastic strength"; "phenomenal feats of memory"
Resembling fantasies in irregularity, caprice, or eccentricity; irregular; oddly shaped; grotesque
existing in fancy only; "fantastic figures with bulbous heads the circumference of a bushel"- Nathaniel Hawthorne
existing in fancy only; "fantastic figures with bulbous heads the circumference of a bushel"- Nathaniel Hawthorne extravagantly fanciful and unrealistic; foolish; "a fantastic idea of his own importance