anything that deludes or misleads by luring on.

Origin of will-o'-the-wisp

1600–10; orig. Will (i.e., William) with the wisp; see wisp
Related formswill·o'-the-wisp·ish; especially British, will·o'-the-wisp·y, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for will-o'-the-wisp



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
a person or thing that is elusive or allures and misleads
Derived Formswill-o'-the-wispish or will-o'-the-wispy, adjective

Word Origin for will-o'-the-wisp

C17: originally Will with the wisp, from Will short for William and wisp in former sense of a twist of hay or straw burning as a torch
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

Word Origin and History for will-o'-the-wisp

1660s, earlier Will with the wisp (c.1600), from the masc. proper name Will + wisp "bundle of hay or straw used as a torch."

Online Etymology Dictionary, © 2010 Douglas Harper