perturbation
nounThe act of perturbing.
nounThe state of being perturbed; agitation.
nounA small change in a physical system, such as a variation in a planet’s orbit resulting from the gravitational influence of other celestial bodies.
nounThe act of perturbing, or the state of being perturbed; disturbance; disorder; especially, disquiet of mind; restlessness or want of tranquillity of mind; commotion of the passions.
nounVariation; especially, irregular or violent variation.
nounA cause of disquiet.
nounIn astronomy, a deviation of the motion of a planet or comet from a fixed orbit or from its regular velocity in that orbit.
nounThe act of perturbing, or the state of being perturbed; esp., agitation of mind.