will o' the wisp

• will-o'-the-wisp, will-o'-wisp, will-in-the-wisp

Will (“male given name”) + of + the + wisp (“bundle of straw or hay used as a torch”)[1]

• (US) IPA^(key): /ˌwɪləðəˈwɪsp/

• Audio (AU)

  (file)

will o' the wisp (plural will o' the wisps)

1. (Britain folklore) A flickering light or lantern, especially over bogs, swamps or marshes, held by a supernatural creature who uses it to lure travelers at night to their demise.
   • 1988, Michael Weikath, "Keeper of the Seven Keys", Helloween, Keeper of the Seven Keys: Part II.

     Will o' the wisps / Misguiding your path / You can't throw a curse / Without takin' their wrath

2. (idiomatic) A delusionary or otherwise unachievable goal that one feels compelled to pursue.
   • 1992 March 2, Richard Preston, The New Yorker, "The Mountains of Pi":

     I happen to think the brothers’ pi project is a will-o’-the-wisp, and is one of the least interesting things they’ve ever done. But what do I know?

• (strange light): ignis fatuus, spooklights, ghost lights, nightfire; hinkypunk (west Country dialect); jack o'lantern (US); walking fire

• Min Min light

• "Will o’ the wisp" at Folklore of the British Isles