phan·ta·si·ast \fan.ˈtāzēˌast, -_ə̇st\noun (-s) Usage: usually capitalized Etymology: Late Greek phantasiastēs, from Greek phantasia appearance, image, imagination + -astēs -ast; from the belief that Christ's body was only a phantom — more at fancy : julianist • phan·ta·si·as·tic\ ̷ ̷| ̷ ̷ ̷ ̷|astik\adjective, usually capitalized