familiarity in WordNet English dictionary

1. personal knowledge or information about someone or something
   acquaintance  familiarity  conversance  conversancy 
   
2. a casual manner
   casualness  familiarity 
   
3. close or warm friendship
   "the absence of fences created a mysterious intimacy in which no one knew privacy"
   familiarity  intimacy  closeness 
   
4. an act of undue intimacy
   familiarity  impropriety  indecorum  liberty 
   
5. usualness by virtue of being familiar or well known
   familiarity