"All a-twitter" is an expression that describes the feeling of being excited, nervous or agitated. It is often used to describe someone who is eagerly anticipating something or someone. There are many synonyms that can be used to convey the same feeling including "anxious," "jittery," "excited," "nervous," "anticipating," "eager," and "apprehensive." Each of these words can be used to describe the same feeling, but they each have their own unique nuance and context. Understanding the subtle differences between these synonyms can help convey precisely the desired tone and meaning in any given context.