1.nounA fearful state; a state of concern or hesitation.
"I decided, with considerable trepidation, to let him drive my car without me."
2.nounAn involuntary trembling, sometimes an effect of paralysis, but usually caused by terror or fear; quaking; quivering.
3.nounA 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.