Wiktionary
champ at the bit
vb. 1 (context intransitive horses English) to bite the bit, especially when restless 2 (context intransitive idiomatic English) (''of a person'') to show impatience or frustration when delayed
Usage examples of "champ at the bit".
Roguesshe sighedmust be dealt with very delicately, lest they champ at the bit.