verb: cause a celestial body to deviate from a theoretically regular orbital motion, especially as a result of interposed or extraordinary gravitational pull
Example: "The orbits of these stars were perturbed by the passings of a comet"
verb: disturb or interfere with the usual path of an electron or atom
Example: "The electrons were perturbed by the passing ion"
verb: throw into great confusion or disorder
Example: "Fundamental Islamicists threaten to perturb the social order in Algeria and Egypt"
verb: disturb in mind or make uneasy or cause to be worried or alarmed
Example: "She was rather perturbed by the news that her father was seriously ill"