fantasm vs illusion

fantasm and illusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
fantasm	Yes	No	No	No
illusion	Yes	No	No	No

As nouns, illusion is a hypernym of fantasm; that is, illusion is a word with a broader meaning than fantasm:

Other hypernyms of fantasm include semblance.

fantasm (noun)	illusion (noun)
something existing in perception only	the act of deluding; deception by creating illusory ideas
a ghostly appearing figure	an illusory feat; considered magical by naive observers
	something many people believe that is false
	an erroneous mental representation