ignoramus

n.

  1. We are ignorant; we ignore; -- being the word formerly written on a bill of indictment by a grand jury when there was not sufficient evidence to warrant them in finding it a true bill. The phrase now used is, "No bill," "No true bill," or "Not found," though in some jurisdictions "Ignored" is still used.
  2. A stupid, ignorant person; a vain pretender to knowledge; a dunce.