1. An image formed by the mind, and supposed to be real or material; a shadowy or airy appearance; sometimes, an optical illusion; a phantom; a dream. They be but phantasms or apparitions. (Sir W. Raleigh)
2. A mental image or representation of a real object; a fancy; a notion. Figures or little features, of which the description had produced in you no phantasm or expectation. (Jer. Taylor)
Origin: L. Phantasma. See Phantom, and cf. Fantasm Spelt also fantasm.