nodding acquaintance vs proximity

nodding acquaintance

noun
  • A casual or partial familiarity; a relationship which is not close or fully developed; an inexact understanding (of something). 

  • Someone who is a remote or passing acquaintance. 

proximity

noun
  • Closeness; the state of being near as in space, time, or relationship. 

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