an·​ti·​vi·​ral | \ ˌan-tē-ˈvī-rəl How to pronounce antiviral (audio) , ˌan-tī-\

Definition of antiviral

 (Entry 1 of 2)

1 medical : acting, effective, or directed against viruses an antiviral vaccine/drug
2 : used to protect a computer from viruses : antivirus antiviral software



Definition of antiviral (Entry 2 of 2)

: an antiviral agent and especially a drug antivirals used in treating influenza

Examples of antiviral in a Sentence

Recent Examples on the Web: Adjective

The Calming Smelling Salts This small, gilded vial is filled with a reinvigorating mix of amethyst and Hawaiian black salts infused with a unique mix of antiviral lavender, patchouli, and peppermint oils designed to ward off germs—and bad energy! Lauren Valenti, Vogue, "How to Turn Your Desk Into the Ultimate Self-Care Station in 2019," 12 Dec. 2018 For genital herpes, you will most likely be prescribed an antiviral medication like Valacyclovir or Acyclovir. Hannah Orenstein, Seventeen, ""I Have a Cold Sore. Does That Mean I Have Herpes?"," 22 Feb. 2019 The pair played key roles transforming Gilead from a fledgling antiviral drugmaker into one of the world’s biggest pharmaceutical companies by sales, though a frequent target of criticism for the high prices of its HIV and hepatitis C drugs. Jonathan D. Rockoff, WSJ, "Gilead Sciences CEO Stepping Down," 25 July 2018 The best hope for that, at the moment, rests on a combination of vaccines to protect the uninfected and antiviral drugs to treat the infected, but the wrong mutation in the virus’ genome could render those weapons useless. Kiona N. Smith, Ars Technica, "Genghis Khan’s Mongol horde probably had rampant Hepatitis B," 11 May 2018 The antiviral needs to be taken within 48 hours of the first signs of infection to be most effective and reduces the duration of flu symptoms by about a day. Sarah Gantz,, "For this family, the flu's final gut punch was an $887 testing charge," 10 Apr. 2018 In the event that existing vaccines provide no protection from a particular new flu threat, antiviral medicines would at least pose a partial first line of defense against the epidemic until a vaccine could be developed. Ron Klain, Vox, "A pandemic killing tens of millions of people is a real possibility — and we are not prepared for it," 15 Oct. 2018 Development of antiviral medicines to treat patients is still in early stages, too. Emily Baumgaertner, New York Times, "High-Resolution Snapshot of Zika Virus Reveals Clues to Fighting It," 26 June 2018 Four experimental treatments for Ebola were sent to the region: ZMapp, which was tried in West Africa; GS-5734, an antiviral drug; and two monoclonal antibodies, REGN-EB3 and Ma b114. New York Times, "Ebola Outbreak in Central Africa Is ‘Largely Contained’," 28 June 2018

Recent Examples on the Web: Noun

There are already a few flu-fighting antivirals out there, the most widely known being Tamiflu (oseltamivir). Korin Miller, SELF, "What You Need to Know About Xofluza, the New Flu Medicine," 26 Oct. 2018 The patients are being treated at Jamaica Hospital Medical Center in Queens, including with antivirals, the CDC said. Betsy Mckay, WSJ, "Sick Emirates Passengers Test Positive For Common Viruses," 6 Sep. 2018 But certain people in high-risk groups — young children, pregnant women, people over age 65, people with other chronic diseases — may want to seek medical attention and antivirals like Tamiflu. Julia Belluz, Vox, "80,000 Americans died of the flu last year. Get your flu shot.," 27 Sep. 2018 The patients were treated with the flu vaccine and antivirals, reported the CDC in a statement. Rachel Becker, The Verge, "CDC investigates two more flights that landed with coughing passengers," 6 Sep. 2018 The experimental treatment can tackle various flu varieties such as H7N9 and H5N1, according to Genentech, and behaves in a different way from other antivirals. Sy Mukherjee, Fortune, "This New Single Dose Flu Drug Could Be Coming to the U.S. Before the Next Flu Season," 28 June 2018 The company, which is not abandoning research into tropical diseases such as malaria, is looking to license its early-stage products and stressed that its Sandoz generics unit continues to manufacture and sell antibiotics and antivirals. Ed Silverman, STAT, "Pharmalittle: Most drug price hikes occurred before Azar arrived; Novartis abandons antibiotics," 12 July 2018 There are antibiotics, including the powerful medication Ciprofloxacin, vaccines for smallpox and anthrax and antivirals for a deadly influenza pandemic. James Hohmann, Washington Post, "The Daily 202: Mick Mulvaney’s confession highlights the corrosive influence of money in politics," 25 Apr. 2018 But the development of more effective antivirals for people who have already been infected is a key element of fighting influenza, too. Sy Mukherjee, Fortune, "Brainstorm Health: 24 Hour Flu Killer, Scott Walker and Obamacare, Drug Regulation Under Trump," 23 Feb. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'antiviral.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of antiviral


1929, in the meaning defined at sense 1


1959, in the meaning defined above

Keep scrolling for more

Learn More about antiviral

Share antiviral

Statistics for antiviral

Last Updated

14 Mar 2019

Look-up Popularity

Time Traveler for antiviral

The first known use of antiviral was in 1929

See more words from the same year

Keep scrolling for more

More Definitions for antiviral


an·​ti·​vi·​ral | \ -ˈvi-rəl How to pronounce antiviral (audio) \
variants: also antivirus \ -​rəs How to pronounce antivirus (audio) \

Medical Definition of antiviral

 (Entry 1 of 2)

: acting, effective, or directed against viruses antiviral drugs



Medical Definition of antiviral (Entry 2 of 2)

: an antiviral agent and especially a drug

More from Merriam-Webster on antiviral

Spanish Central: Translation of antiviral

Comments on antiviral

What made you want to look up antiviral? Please tell us where you read or heard it (including the quote, if possible).


the range of authority or knowledge

Get Word of the Day daily email!

Test Your Vocabulary

Original Meanings Quiz

  • rembrandt-painting-a-young-scholar-and-his-tutor
  • Which of the following is the earliest known sense of the word awe?
True or False

Test your knowledge - and maybe learn something along the way.


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!