will-o'-the-wisp vs ignis fatuus

will-o'-the-wisp and ignis fatuus both are nouns.

Word	Noun	Adjective	Verb	Adverb
will-o'-the-wisp	Yes	No	No	No
ignis fatuus	Yes	No	No	No

As nouns, will-o'-the-wisp and ignis fatuus are synonyms defined as:

As nouns, will-o'-the-wisp and ignis fatuus are synonyms defined as:

will-o'-the-wisp and ignis fatuus: a pale light sometimes seen at night over marshy ground

Other synonyms of will-o'-the-wisp include friar's lantern, jack-o'-lantern.

will-o'-the-wisp (noun)	ignis fatuus (noun)
an illusion that misleads	an illusion that misleads
a pale light sometimes seen at night over marshy ground	a pale light sometimes seen at night over marshy ground