underpants gnome

noun2

1. •
   (slang) Someone who makes incomplete plans with missing steps; someone who plans unsuccessfully.

   • 2. ? 3. Profit! Do you think their plan is missing something? They know Success in Programming 53 There Is No Try It's a Question of Passion Don't Plan Like an Underpants Gnome. — 2014
2. •
   [before a noun] (slang) A plan with missing steps; an incomplete plan.