The Oxford Thesaurus An A-Z Dictionary of Synonyms - familiarityn.

1) knowledge, acquaintance(ship) , grasp, understanding, comprehension, cognizance, awareness, conversance, experience: I have no familiarity at all with particle physics. 2) friendliness, affability, sociability, neighbourliness, fellowship, intimacy, intimateness, closeness, openness, naturalness, ease, informality, unceremoniousness: He prided himself on his familiarity with celebrities. 3) boldness, presumptuousness, overfamiliarity, presumption, impudence, insolence, impertinence, impropriety: He put his arm round her waist with offensive familiarity.