Keyed-up is a term used to describe a person who is feeling excited, nervous, or anxious. Some antonyms for the word keyed-up include calm, relaxed, composed, tranquil, serene, and at ease. These words describe a person who is not experiencing any intense emotions or is devoid of any stress or agitation. When a person is feeling calm, they are at peace with themselves and the situations around them. On the other hand, when a person is keyed-up, they may find it challenging to focus on tasks at hand, and it can have a negative impact on their mental and physical health. Thus, it is essential to find ways to remain relaxed and calm in stressful situations.