nullification vs skill

nullification

noun
  • The nullification crisis in U.S. history, confrontation between the state of South Carolina and the federal government in 1832–33 over the former's attempt to declare null and void within the state the federal Tariffs of 1828 and 1832. 

  • Surgical removal of genitals (and sometimes nipples) as a form of body modification; a person who has undergone this surgery is a nullo. 

  • The act of nullifying; a rendering void and of no effect, or no legal effect. 

skill

verb
  • To know; to understand. 

  • To have knowledge or comprehension; discern. 

  • To set apart; separate. 

  • To discern; have knowledge or understanding; to know how (to). 

  • To have personal or practical knowledge; be versed or practised; be expert or dextrous. 

  • To spend acquired points in exchange for skills. 

adj
  • Great, excellent. 

noun
  • Capacity to do something well; technique, ability. Skills are usually acquired or learned, as opposed to abilities, which are often thought of as innate. 

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