1. excessive or exaggerated seriousness, intensity, or sincerity in manner, speech, or effort
Usage: typically used to describe behavior or attitude that is more serious or intense than the situation warrants

Examples

• His overearnestness about the school project made him seem uptight to his classmates.
• The coach's overearnestness during practice drills left the team feeling exhausted and discouraged.
• She appreciated his help, but his overearnestness in explaining every detail was tiresome.
• The overearnestness of the speech made it difficult for the audience to connect with the speaker.
• His overearnestness about following rules sometimes prevented him from enjoying social situations.
• The film's overearnestness undermined its attempt at comedy.