(ˈ)fan.|tastə̇k(ə)lē, -aan-, fən.ˈt-, -taas-, -stēk-, -li adverb
1. : in a fantastic manner : grotesquely , oddly
a fantastically plotted novel
2. : to a fantastic degree : unbelievable , extremely
fantastically expensive clothes
3. archaic : capriciously