1. excessive or immoderate enthusiasm, eagerness, or devotion to a cause, belief, or activity
Usage: uncountable noun; often implies misguided or counterproductive intensity

Examples

• Her overzealousness in promoting the new policy alienated many colleagues.
• The coach's overzealousness during practice resulted in several player injuries.
• His overzealousness to please the boss led him to work unpaid overtime every week.
• The committee's overzealousness in enforcing rules created unnecessary conflict.
• She regretted her overzealousness in criticizing her friend's life choices.
• The organization's overzealousness about fundraising made donors uncomfortable.