ignorant vs tip of the iceberg

ignorant

adj
  • Ill-mannered, crude. 

  • Resulting from ignorance; foolish; silly. 

  • Not knowing (a fact or facts), unaware (of something). 

  • Unknowledgeable or uneducated; characterized by ignorance. 

noun
  • One who is ignorant. 

tip of the iceberg

noun
  • A small indication of a larger possibility; the first part encountered of a problem that is much bigger than it seems. 

How often have the words ignorant and tip of the iceberg occurred in a corpus of books? (source: Google Ngram Viewer )