trepidation

noun

Etymology: Borrowed from Latin trepidātiō, from trepidō (“be agitated”).

1. Anxiety over the uncertain future or possible ill-occurrence.

   “I decided, with considerable trepidation, to let him drive my car without me.”

   “She reached it soon after half-past two. She found its gloomy nineteenth-century façade, black with the smuts of ninety years, a little daunting, and mounted its broad steps in some trepidation. But she rang the bell hard and knocked firmly.”

2. An involuntary trembling, sometimes an effect of paralysis, but usually caused by terror or fear.
3. A libration of the starry sphere in the Ptolemaic system; a motion ascribed to the firmament, to account for certain small changes in the position of the ecliptic and of the stars.