Eager Beaver
Canadian SlangDefinition
A very enthusiastic, hardworking person, sometimes to an excessive or annoying degree.
Examples
"Our new intern is a real Eager Beaver—she’s already organized the files and volunteered for three extra projects."
"Don’t be such an Eager Beaver; the report isn’t due until Friday, and you’re stressing everyone out."
"The coach loves having an Eager Beaver on the team who shows up early to every practice and stays late to run drills."