The phrase "coming across with" implies cooperation or agreement, which means the antonyms will be terms that signify disagreement or refusal. Some antonyms of "coming across with" include disagreeing, contradicting, disputing, rejecting or declining. When you disagree with someone, you are not on the same page as they are, and you do not see things the same way. Contradicting means to assert the opposite of something someone just said. Disputing involves disagreeing or arguing over an idea or statement. Rejecting refers to refusing a proposal or an offer, while declining means to say no or refuse politely. All these words are antonyms to "coming across with," and they signify resistance rather than agreement.