epidemic

noun

1. A widespread disease that affects many humans in a population.

   “At that time, the city [Christiania, now Oslo] was in the grip of a cholera epidemic, and victims were dying at the rate of 60 a day. Bradshaw contracted the disease, and died on September 6 [1853].”

2. An occurrence of a disease or disorder in a human population at a frequency higher than that expected in a given time period; an episode of outbreak and subsequent high prevalence.
3. (broadly, colloquial)A heightened occurrence of anything harmful.

   “Even before the pandemic, the United States surgeon general, Vivek Murthy, said the country was experiencing an “epidemic of loneliness,” driven by the accelerated pace of life and the spread of technology into all of our social interactions.”

   “People are holding coordinated protests across UK towns and cities this weekend against what they call a “climate of fear” on the roads, and an “epidemic” of careless and dangerous driving that is curbing children’s freedoms and putting lives at risk.”

4. (figuratively)The spreading of an idea or belief amongst a population.

   “Lord Avonleigh was at once liberated from his imprisonment, well prepared to be considered, and to consider himself, a martyr to the cause of loyalty; and as the services of the rich nobleman,...his claims to notice and favour were most graciously acknowledged. Accordingly, he returned to his seat in a little fever of royal devotedness—it was the fashionable epidemic; and who coming from Whitehall could be without it?”

adj

1. Of, related to, or being an epidemic: a widespread outbreak of disease in humans.
2. (figuratively)Like an epidemic: widespread in a bad way.

   “Epidemic hysteria occurred upon the incumbent’s reelection.”

   “[In] May, there was, at London and in its neighbourhood, a disease very epidemic, though not fatal, which had some time before been very prevalent both in Italy and Germany.”

   “The major reason for such an examination was to determine if any patterns uncovered seemed to be more epidemic than endemic.”

   “This proportion increased about 5% from 1988 to 1992—hardly a change of epidemic proportions.”

   “This was the stagecoach holdup, and while these encounters were not as epidemic as we like to remember, nonetheless there were numerous bands of "road agents" who lay by the roadside in wait for passengers.”