will-o'-the-wisp \ˈwiləthəˈwisp\noun alsowill-of-the-wisp\-ləfth-\ Etymology:Will (nickname for William) + of + the + wisp 1.: ignis fatuus 2.: a delusive goal < followed the will-o'-the-wisp of universal disarmament — G.F.Eliot > • will-o'-the-wisp·ish\-pish\adjective