acumen vs understanding

acumen

noun
  • Quickness of perception or discernment; penetration of mind; the faculty of nice discrimination. 

  • A bony, often sharp, protuberance, especially that of the ischium. 

  • A sharp, tapering point extending from a plant. 

understanding

noun
  • The act of one that understands or comprehends; comprehension; knowledge; discernment. 

  • Opinion, judgement or outlook. 

  • An informal contract; mutual agreement. 

  • A reconciliation of differences. 

  • Sympathy. 

  • Reason or intelligence, ability to grasp the full meaning of knowledge, ability to infer. 

adj
  • Showing compassion, tolerance, and forbearance. 

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