ignis fatuus vs fancy

ignis fatuus and fancy both are nouns.

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

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

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

ignis fatuus (noun)	fancy (noun)
an illusion that misleads	imagination or fantasy; held by Coleridge to be more casual and superficial than true imagination
a pale light sometimes seen at night over marshy ground	something many people believe that is false
	a predisposition to like something

ignis fatuus (adjective)	fancy (adjective)
	not plain; decorative or ornamented

ignis fatuus (verb)	fancy (verb)
	imagine; conceive of; see in one's mind
	have a fancy or particular liking or desire for