Fantastic, a.
Etymology: [F. fantastique, fr. Gr. 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.
1 more senses
Syn. -- Fanciful; imaginative; ideal; visionary; capricious; chimerical; whimsical; queer. See Fanciful.
1 other Webster entry under this spelling
Fantastic, n.
A person given to fantastic dress, manners, etc.; an eccentric person; a fop. Milton. Our fantastics, who, having a fine watch, take all ocasions to drow it out to be seen. Fuller.
Shades of meaning
Fernald has no entry of its own for fantastic; he lists it under fanciful, queer.
Where he writes about it:
That is fanciful which is dictated or suggested by fancy independently of more serious considerations; the fantastic is the fanciful with the added elements of whimsicalness and extravagance. — from fanciful
The fanciful swings away from the real or the ordinary lightly and pleasantly, the fantastic extravagantly, the grotesque ridiculously. — from fanciful
A fanciful arrangement of objects is commonly pleasing, a fantastic arrangement is striking, a grotesque arrangement is laughable. — from fanciful
Fantasy in ordinary usage simply denotes capricious or erratic fancy, as appears in the adjective fantastic. — from imagination