Enthusiastic means showing intense excitement, interest, or eagerness about something. When you're enthusiastic about a new book, you can't wait to read it and you tell everyone how great it is. When your friend is enthusiastic about soccer, they practice constantly and light up whenever someone mentions the game.

The word comes from Greek roots meaning “inspired by a god,” which gives you a sense of how powerful real enthusiasm feels. It's that energized, can't-sit-still feeling that makes you want to dive in completely and lose yourself in whatever excites you.

You can spot enthusiasm in someone's voice (louder, faster, more animated), their body language (leaning forward, gesturing), and their actions (volunteering first, asking questions, wanting to help). An enthusiastic reader doesn't just finish their assignment; they read ahead and bring the book to lunch. An enthusiastic scientist doesn't just complete the experiment; they design new ones on their own time.

The opposite would be apathetic or indifferent, showing no real interest at all. Enthusiasm (the noun form) is contagious: when one student shows genuine enthusiasm for a project, others can get excited too.