Antonyms for the phrase "most keyed-up" may include words like calm, relaxed, serene, placid, peaceful, tranquil, composed, collected, nonchalant, cool, and equanimous. While "most keyed-up" describes an individual who is highly excited, nervous, or anxious, these antonyms suggest a sense of inner peace, tranquillity, and composure. For example, instead of feeling "most keyed-up" before a big presentation, one might feel calm, collected, and composed. By understanding the antonyms of the phrase "most keyed-up," individuals can identify their emotions and work towards achieving a state of relaxation and peace.