The phrase "are prolix" refers to being overly verbose or long-winded. Antonyms for this phrase include concise, brief, succinct, pithy, and terse. These words describe communication that is clear and to the point, without unnecessary elaboration or repetition. Concise language communicates complex ideas efficiently, making it easier for the listener or reader to comprehend the message. Conversely, using prolix language can cause confusion and frustration, as the listener may struggle to identify the central message or distinguish between important and extraneous details. Therefore, using concise language is often preferred in professional and academic settings, where time and clarity are of the essence.