late 14c., "existing only in imagination, produced by (mental) fantasy," from Old French fantastique (14c.), from Medieval Latin fantasticus, from Late Latin phantasticus "imaginary," from Greek phantastikos "able to imagine," from phantazein "make visible" (middle voice phantazesthai "picture to oneself"); see phantasm. Trivial sense of "wonderful, marvelous" recorded by 1938. Old French had a different adjective form, fantasieus "weird; insane; make-believe." Medieval Latin also used fantasticus as a noun, "a lunatic," and Shakespeare and his contemporaries had it in Italian form fantastico "one who acts ridiculously."
1570s, from Italian Italianato "rendered Italian," from Italiano (see Italian). In older use "applied especially to fantastic affectations of fashions borrowed from Italy" [Century Dictionary], or in reference to the supposed Italian proverb that translates as an Englishman Italianate is a Devil incarnate which circulated in English (there also was a version in Germany about Italianized Germans).
traditional English dance of persons in costume, mid-15c., moreys daunce "Moorish dance," from Flemish mooriske dans, from Old French morois "Moorish, Arab, black," from More "Moor" (see Moor). It is unknown why the English dance (which typically is based on the Robin Hood stories) was called this, unless it is in reference to fantastic dancing or costumes (compare Italian Moresco, a related dance, literally "Moorish;" German moriskentanz, French moresque).
1709, "ancient Scandinavian legend of considerable length," an antiquarians' revival to describe the medieval prose narratives of Iceland and Norway, from Old Norse saga "saga, story," cognate with Old English sagu "a saying" (see saw (n.2)).
Properly a long narrative composition of Iceland or Norway in the Middle Ages featuring heroic adventure and fantastic journeys, or one that has their characteristics. The extended meaning "long, convoluted story" is by 1857.