Illusory (adjective)

1. Based on or having the nature of an illusion; misleading; deceptive.
2. Not real; existing only in the imagination.

Origin:

From latin illusorius, from illusus, past participle of illudere "to mock".

Examples:

1. The mirage made the desert appear to be a lake, but it was an illusory image.
2. He had an illusory belief that he could become rich without working.
3. The promise of easy money proved to be illusory and many investors lost their savings.
4. The movie special effects created an illusory world that seemed completely real.
5. The illusory nature of the advertisement made it difficult to tell what was real and what was not.