Italian word fantastico comes from Ancient Greek (to 1453) φᾰντᾰστῐκός.

Fantastico etymology ^?

Fantastico detailed word origin explanation

Dictionary entry	Language	Definition
φᾰντᾰστῐκός	Ancient Greek (to 1453) (grc)
phantasticus	Late Latin (LL)
fantastico	Italian (ita)	(colloquial) fantastic, wonderful, great, terrific. Fabulous, imaginary, imaginative, fantastic.