fantastic

The best instances of fantastic i can give you:
Hieronymus Bosch, particularly his painting the Garden of Earthly Delights.
Alice in Wonderland! by Lewis Carroll.
Anything written by Gabriel García Márquez. Amen, Kurt Vonnegut.
The Tragical Comedy, or the Comical Tragedy of Mr Punch, an artful comic.
Fantastic is Art Nouveau, Cyberpunk Fiction, German Expressionist Film. It is most definitely Glam Rock. A particular brand of Horror. Magical Realism.

Fan*tas"tic (?), a. [F. fantastique, fr. Gr. able to represent, fr. to make visible. See Fancy.]

1.

Existing only in imagination; fanciful; imaginary; not real; chimerical.

2.

Having the nature of a phantom; unreal.

Shak.

3.

Indulging the vagaries of imagination; whimsical; full of absurd fancies; capricious; as, fantastic minds; a fantastic mistress.

4.

Resembling fantasies in irregularity, caprice, or eccentricity; irregular; oddly shaped; grotesque.

There at the foot of yonder nodding beech, That wreathes its old fantastic roots so high.
T. Gray.

Syn. -- Fanciful; imaginative; ideal; visionary; capricious; chimerical; whimsical; queer. See Fanciful.

© Webster 1913.

Fan*tas"tic, n.

A person given to fantastic dress, manners, etc.; an eccentric person; a fop.

Milton.

Our fantastics, who, having a fine watch, take all occasions to drow it out to be seen.
Fuller.

© Webster 1913.