cosmetic vs tip of the iceberg

cosmetic

noun
  • An intangible influence that improves the overall perception of some thing or situation. 

  • A feature existing only on the surface. 

  • Any substances applied to enhance the external color or texture of the skin, e.g. lipstick, eyeshadow, eyeliner; makeup. 

adj
  • External or superficial; pertaining only to the surface or appearance of something. 

  • Imparting or improving beauty, particularly the beauty of the complexion. 

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 cosmetic and tip of the iceberg occurred in a corpus of books? (source: Google Ngram Viewer )