great worry or fear about something unpleasant that may happen 惊恐；恐惧；惊惶；不安 He knocked on the door with some trepidation. 他有些不安地敲了敲门。
Word Originlate 15th cent.: from Latin trepidatio(n-), from trepidare ‘be agitated, tremble’, from trepidus ‘alarmed’.