familiarity

Etymology

From Middle French familiarité, from Latin familiāritātem. Displaced native Old English hīwcūþnes. Morphologically familiar + -ity

noun

1. The state of being extremely friendly; intimacy.
   Do not keep familiarity with any but those, with whom you may improve your time. 1677, Hannah Woolley, The Compleat Servant-Maid, London: T. Passinger, page 2
2. Undue intimacy; inappropriate informality, impertinence.
   Murrel did not in the least object to being called a monkey, yet he always felt a slight distaste when Julian Archer called him one.[…]It had to do with a fine shade between familiarity and intimacy which men like Murrel are never ready to disregard, however ready they may be to black their faces. 1927, G K Chesterton, The Return of Don Quixote, page 5
3. An instance of familiar behaviour.
4. Close or habitual acquaintance with someone or something; understanding or recognition acquired from experience.