ignis fatuusig·nis fat·u·us
nounpl. ig′nes fat′ui·
- a light seen at night moving over swamps or marshy places, believed to be caused by the combustion of gases arising from decaying organic matter: popularly called will-o'-the-wisp
- a deceptive hope, goal, or influence; delusion
Origin of ignis fatuusMedieval Latin from Classical Latin ignis, a fire + fatuus, foolish
nounpl. ig·nes fat·u·i,
- A phosphorescent light that hovers or flits over swampy ground at night, possibly caused by spontaneous combustion of gases emitted by rotting organic matter. Also called friar's lantern . Also called jack-o'-lantern . Also called will-o'-the-wisp . Also called wisp .
- Something that misleads or deludes; an illusion.
Origin of ignis fatuusMedieval LatinLatin ignis fire Latin fatuus foolish
(plural ignes fatui)
- A will o' the wisp.
- (figuratively) A delusion, a false hope.
Modern Latin, from ignis (“fire”) + fatuus (“foolish”). Literally "foolish fire".