noun

1. A fanciful or whimsical person.

adjective

1. Existing in or constructed from fantasy; of or relating to fantasy; fanciful.

   “He told fantastic stories of dragons and goblins.”

2. Not believable; implausible; seemingly only possible in fantasy.

   “She entered the lab and stood gaping for a good ten minutes at the fantastic machinery at work all around her.”

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

Synonyms: fabulous, fantastical, foolish, hare-brained, unrealistic, wild, brilliant, fabulous