There are several synonyms for the phrase "chafing the bit." One alternative is "chomping at the bit," which means to be impatient and eager to do something. Another option is "itching to go," which has a similar meaning, implying a strong desire to start or move forward. "Restive," on the other hand, suggests a sense of frustration and impatience, as well as an inability to stay still or calm. "Antsy" is another synonym that conveys a sense of unease and restlessness, often with the implication of being eager to get going or do something productive. Overall, there are many ways to express the idea of being impatient and eager to act - it all depends on the context and the tone of the conversation.