Going on a tear refers to a spree of energetic and enthusiastic behavior. Antonyms for this phrase would include words like subdued, inactive, serene, and relaxed. These words imply a sense of quiet and calm, as opposed to the frenetic and excited energy that going on a tear implies. Other antonyms might include words like lethargic, withdrawn, apathetic, and uninterested, which suggest a lack of motivation or enthusiasm altogether. Going on a tear is often associated with excessive or uncontrolled behavior, so antonyms that suggest control, balance, or moderation may also be employed, such as measured, contained, or restrained.