The term "putting across" is often used to describe the act of communicating effectively or making oneself understood. The antonyms for "putting across" would essentially be the opposite actions or qualities that hinder effective communication, such as being evasive, unclear, confusing, or inarticulate. To prevent effective communication, one might resort to tactics like being vague, using complicated words, using negative tone or body language, or avoiding the issue altogether. Conversely, qualities like clarity, simplicity, openness, and directness would be the antonyms of "putting across," as these facilitate effective communication and help get the intended message across to the listener or audience.