brittleness vs chink in the armor

brittleness

noun
  • The state of being brittle; aptness to break; fragility. 

  • The property by virtue of which a material is fractured without appreciable deformation by the application of load. 

chink in the armor

noun
  • A weakness; a weak point (particularly of something formerly considered near-invincible or perfect). 

How often have the words brittleness and chink in the armor occurred in a corpus of books? (source: Google Ngram Viewer )