Antonyms are words that are opposite in meaning to each other. For the phrase "Timed Vital Capacity," some antonyms could be: untimed, static, limited, erratic, unpredictable, irregular, sporadic, and inconsistent. Untimed would mean not being constrained by a specific duration, whereas static would indicate a lack of movement or change. Limited would show that the amount is restricted, and erratic would suggest an unpredictable pattern. Unpredictable, sporadic, and inconsistent would indicate that the capacity varies widely and is not reliable. These antonyms show an opposing meaning to the initial phrase, highlighting its temporal or measurable nature.