adj having the nature of a phantom; unreal.
2. fantastic ·adj existing only in imagination; fanciful; imaginary; not real; chimerical.
3. fantastic ·noun a person given to fantastic dress, manners, ·etc.; an eccentric person; a fop.
4. fantastic ·adj resembling fantasies in irregularity, caprice, or eccentricity; irregular; oddly shaped; grotesque.
5. fantastic ·adj indulging the vagaries of imagination; whimsical; full of absurd fancies; capricious; as, fantastic minds; a fantastic mistress.