an epidemic disease that causes high mortality; pestilence.
an infectious, epidemic disease caused by a bacterium, Yersinia pestis, characterized by fever, chills, and prostration, transmitted to humans from rats by means of the bites of fleas. Compare bubonic plague, pneumonic plague, septicemic plague.
any widespread affliction, calamity, or evil, especially one regarded as a direct punishment by God: a plague of war and desolation.
any cause of trouble, annoyance, or vexation: Uninvited guests are a plague.
to trouble, annoy, or torment in any manner: The question of his future plagues him with doubt.