Antonyms for the phrase "ants in pants" would include feelings of calm, relaxation, and tranquility. These antonyms convey a sense of peace and contentment, rather than the restlessness and agitation implied by the original phrase. Other antonyms might include lethargy, apathy, and stillness, which indicate a lack of movement and energy rather than an excess of it. Another way to think about antonyms for "ants in pants" is to look for words that describe states of mind or emotions that are completely different from the frenzied excitement suggested by the phrase, such as serenity, composure, and equanimity.