ignis fatuus vs fantasy

ignis fatuus and fantasy both are nouns.

Word	Noun	Adjective	Verb	Adverb
ignis fatuus	Yes	No	No	No
fantasy	Yes	No	Yes	No

As nouns, fantasy is a hypernym of ignis fatuus; that is, fantasy is a word with a broader meaning than ignis fatuus:

Other hypernyms of ignis fatuus include fancy, illusion, phantasy.

ignis fatuus (noun)	fantasy (noun)
an illusion that misleads	imagination unrestricted by reality
a pale light sometimes seen at night over marshy ground	something many people believe that is false
	fiction with a large amount of imagination in it

ignis fatuus (verb)	fantasy (verb)
	indulge in fantasies