familiarity

(noun) personal knowledge or information about someone or something. Synonyms: acquaintance, conversance, conversancy.

(noun) usualness by virtue of being familiar or well known.

(noun) close or warm friendship. Synonyms: intimacy, closeness. Example: "The absence of fences created a mysterious intimacy in which no one knew privacy."

(noun) a casual manner. Synonyms: casualness.

(noun) an act of undue intimacy. Synonyms: impropriety, indecorum, liberty.