Enthusiasm By Happiness Posted on December 14, 2022 « Back to Glossary IndexA Marine Corps Leadership Trait for Parents. Enthusiasm is defined as a sincere interest and exuberance in the performance of your duties. If you are enthusiastic, you are optimistic, cheerful, and willing to accept the challenges. Suggestions for Improvement: Understanding and belief in your mission will add to your enthusiasm for your job. Try to understand why even uninteresting jobs must be done. « Back to Glossary Index