noun
: one who is overzealous, overdiligent, and impatient not only to perform his part with promptness but to volunteer for more
was an eager beaver, always doing more than he was told, always studying — Joseph Wechsberg
noun
: one who is overzealous, overdiligent, and impatient not only to perform his part with promptness but to volunteer for more
was an eager beaver, always doing more than he was told, always studying — Joseph Wechsberg
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012