will-o'-the-wisp

American  

[wil-uh-thuh-wisp] / ˈwɪl ə ðəˈwɪsp /

noun

1. ignis fatuus.

2. anything that deludes or misleads by luring on.

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will-o'-the-wisp British  

/ ˌwɪləðəˈwɪsp /

noun

1. Also called: friar's lantern.   ignis fatuus.   jack-o'-lantern.  a pale flame or phosphorescence sometimes seen over marshy ground at night. It is believed to be due to the spontaneous combustion of methane or other hydrocarbons originating from decomposing organic matter

2. a person or thing that is elusive or allures and misleads

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Other Word Forms

• will-o'-the-wispish
  adjective
• willo'-the-wispish
  adjective

Etymology

Origin of will-o'-the-wisp

1600–10; originally Will (i.e., William) with the wisp; see wisp