The antonyms for the word "un-communicativeness" are communication, sociability, openness, talkativeness, gregariousness, loquacity, volubility, and friendliness. Communication refers to exchanging information or ideas through speaking, writing, or other means. Sociability suggests a friendly and outgoing nature that seeks company and companionship. Openness implies a willingness to share thoughts, feelings, and ideas without reservation. Talkativeness denotes a tendency to talk or chatter excessively. Gregariousness indicates a liking for being around people and socializing. Loquacity implies a talkative and verbose nature. Volubility suggests an ease and fluency in talking. Finally, friendliness suggests a warm and amicable nature that is approachable and easy to get along with.