Familiarity

The state of being familiar; intimate and frequent converse, or association; unconstrained intercourse; freedom from ceremony and constraint; intimacy; as, to live in remarkable familiarity.

Anything said or done by one person to another unceremoniously and without constraint; esp., in the pl., such actions and words as propriety and courtesy do not warrant; liberties.

personal knowledge or information about someone or something

an act of undue intimacy

close or warm friendship; "the absence of fences created a mysterious intimacy in which no one knew privacy"