ignis fatuus

Modern Latin, from ignis (“fire”) + fatuus (“foolish”). Literally "foolish fire".

• IPA^(key): /ˈɪɡnɪs ˈfætjuːəs/

ignis fatuus (plural ignes fatui)

1. A will o' the wisp.
   • 1621, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy, Oxford: Printed by Iohn Lichfield and Iames Short, for Henry Cripps, OCLC 216894069; The Anatomy of Melancholy: […], 2nd corrected and augmented edition, Oxford: Printed by John Lichfield and James Short, for Henry Cripps, 1624, OCLC 54573970, (please specify |partition=1, 2, or 3):

     , New York, 2001, p.190:

     Fiery spirits or devils are such as commonly work by blazing stars, fire-drakes, or ignes fatui; which lead men often in flumina aut præcipitia, saith Bodine […].

   • 1663, Hudibras, by Samuel Butler, part 1, canto 1

     […] An ignis fatuus, that bewitches, \ And leads men into pools and ditches [...]

2. (figuratively) A delusion, a false hope.
   • 1660, William Petty, Reflections upon Ireland, p. 55:

     ..... they think this is written on purpose to be published; and that this defence is so published, that it may serve as an Ignis fatuus to mislead them.....

   • 1985, Cormac McCarthy, Blood Meridian,

     Like some ignis fatuus belated upon the road behind them which all could see and of which none spoke. For this will to deceive that is in things luminous may manifest itself likewise in retrospect and so by sleight of some fixed part of a journey already accomplished may also post men to fraudulent destinies.

   • 2007, Clive James, Cultural Amnesia, Picador 2007, p. 805:

     But he was slow – painfully slow, hour after hour slow, sweating and struggling in front of his own class slow – to accept the truth about the simple statement: the truth being that it is an ignis fatuus.