Trepidation (noun)

A feeling of fear or agitation about something that may happen.

Origin:

From latin trepidatio ("trembling, agitation"), from trepidus ("trembling, agitated"), from trepidare ("to tremble, be agitated").

Examples:

1. He approached the task with trepidation.
2. She spoke with trepidation about the future.
3. The thought of flying filled him with trepidation.
4. He faced the challenge with trepidation.
5. The idea of public speaking filled her with trepidation.