adj. (also fantastical) 1 colloq. excellent, extraordinary. 2 extravagantly fanciful; capricious, eccentric. 3 grotesque or quaint in design etc. fantasticality n. fantastically adv.
[ ME f. OF fantastique f. med.L fantasticus f. LL phantasticus f. Gk phantastikos (as FANTAST) ]