Unenthusiastic (adjective)

Not showing or feeling enthusiasm.

Origin:

From the prefix un- meaning not and the word enthusiastic.

Examples:

1. He was unenthusiastic about the idea.
2. She was unenthusiastic about going to the party.
3. The unenthusiastic crowd was not responsive to the performance.
4. The unenthusiastic employee was not motivated to work.
5. The unenthusiastic customer was not interested in buying anything.