illusory /ɪˈluː.sə.ɹiː/ adjective1 •Resulting from an illusion; deceptive, imaginary, unreal.The invalidity of a cognition is the otherwiseness of its object, and is known by a sublating cognition. The illusory cognition of silver knows illusory silver, but does not know its otherwiseness. — 1973 formsmore illusory · most illusory