Be champing at the bit American British phrase
"Chomping at the bit" is also used in US.
Be unwilling to wait to do something or for something to happen
She is champing at the bit to leave the classroom as today she has a date with her boyfriend after school.
At this time that morning, I was champing at the bit to take part in my first Marathon.
What a sultry afternoon! My kids are champing at the bit to go swimming.
To start doing something decisively and energetically
Ecstatic and mentally ready (for something).
To lose one's patience.
Commonly seen in progressive tenses( present or past).
This idiom originates from the king's hobby of horse racing. A bit is a piece of equipment that goes in the horse's mouth and attaches to the bridle and reins, allowing the jockey on the back to guide and steer the horse. The bit is designed to fit into a toothless ridge in the horse's muzzle, but the horse never bites it.However, it is possible for the horse to grit his teeth or jaw against the bit, which indicates that the horse is either anxious or very enthusiastic about racing. That's how the word "champing at the bit" came into common usage: to express excessive eagerness.