trepidation

A fearful state; a state of concern or hesitation.

An involuntary trembling, sometimes an effect of paralysis, but usually caused by terror or fear; quaking; quivering.

(astronomy, obsolete) 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.