GNU Collaborative International Dictionary of English

Found one definition

1.       
   Ignoramus , n. [L., we are ignorant. See Ignore.]
   (Law) 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.
   Wharton (Law Dict. ). Burn.
   
   1913 Webster
   (pl. Ignoramuses .) A stupid, ignorant person; a vain pretender to knowledge; a dunce.
   1913 Webster
   An ignoramus in place and power.
   South.
   
   1913 Webster