side effect

or side-ef·fect

noun

1. any effect of a drug, chemical, or other medicine that is in addition to its intended effect, especially an effect that is harmful or unpleasant.
2. any accompanying or consequential and usually detrimental effect:

   the side effects of air pollution.

side effect

noun

1. See aftereffect
   any unwanted nontherapeutic effect caused by a drug Compare aftereffect
2. any secondary effect, esp an undesirable one

Word History and Origins

Origin of side effect¹

First recorded in 1880–85

Example Sentences

He actively sought to play down the threat posed by the virus to buttress the economy before his reelection bid, with the side effect that Republicans were much less likely than Democrats to consider the virus an issue that warranted concern.

From Washington Post

Looking back, they mostly seem like a tone-deaf way to celebrate the side effects of a virus that has devastated millions of people.

From Outside Online

Even if you’re far down the list, it’s important to know what to do before you roll up your sleeve—from how to make the most of the shot, to how to prepare for the possible side effects.

From Popular-Science

A 20% average open rate is not bad, he added, but he said that while BDG focuses on growing its total list size, it will be important to monitor that engagement does not drop off as a side effect of new subscriptions.

From Digiday

Since the beach trip, he has seen cardiologists about his lingering chest pains and finds himself fretting over “the unknown” of what other long-term side effects may emerge.

From Washington Post

But millions of rules result in perpetual error, and, as a terminal side effect, make leadership and accomplishment illegal.

From The Daily Beast

“It was a weird side effect of the cold medicine,” he told me once.

From The Daily Beast

It helps to maintain good posture while doing this—a nice side effect.

From The Daily Beast

One predicted side effect of inflation is primordial gravitational waves: twisty ripples in the structure of the Universe.

From The Daily Beast

Halpern prescribes the medi-meth for patients who get recurrent urinary-tract infections—a side effect from Adderall or Ritalin.

From The Daily Beast

Any complex system is sport for a hacker; a side effect of this is the hacker's natural affinity for problems involving security.

From Project Gutenberg

Related Words

• aftereffect
• reaction