<p><strong>Noun</strong></p><ul><li>the act of perturbing.</li><li>the state of being perturbed.</li><li>mental disquiet, disturbance, or agitation.</li><li>a cause of mental disquiet, disturbance, or agitation.</li><li>Astronomy: deviation of a celestial body from a regular orbit about its primary, caused by the presence of one or more other bodies that act upon the celestial body.</li></ul>