ignis fatuus

[ ig-nis fach-oo-uhs ]
See synonyms for ignis fatuus on Thesaurus.com
noun,plural ig·nes fat·u·i [ig-neez fach-oo-ahy]. /ˈɪg niz ˈfætʃ uˌaɪ/.
  1. Also called friar's lantern, will-o'-the-wisp. a flitting phosphorescent light seen at night, chiefly over marshy ground, and believed to be due to spontaneous combustion of gas from decomposed organic matter.

  2. something deluding or misleading.

Origin of ignis fatuus

1
1555–65; <Medieval Latin: literally, foolish fire

Words Nearby ignis fatuus

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use ignis fatuus in a sentence

  • This was doubtless a true ignis fatuus, and the circumstances necessary to produce it were then present, viz.

  • Thus far the Hofrath; who vanishes, as is his wont, too like an ignis fatuus, leaving the dark still darker.

    Sartor Resartus | Thomas Carlyle
  • Still the ignis fatuus of a shorter route to India tantalized the early navigators.

    The Greater Republic | Charles Morris
  • He had not been imposed upon by his fancy; he had not been deceived by some ignis fatuus.

    Bible Emblems | Edward E. Seelye
  • It is, in truth, a shadow as intangible as our own; an ignis fatuus of our being.

British Dictionary definitions for ignis fatuus

ignis fatuus

/ (ˈɪɡnɪs ˈfætjʊəs) /


nounplural ignes fatui (ˈɪɡniːz ˈfætjʊˌaɪ)
  1. another name for will-o'-the-wisp

Origin of ignis fatuus

1
C16: from Medieval Latin, literally: foolish fire

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012