radioactive
adjective
ra·dio·ac·tive
ˌrā-dē-ō-ˈak-tiv 
1
: of, caused by, or exhibiting radioactivity
radioactive isotopes
Radon is an odorless, colorless gas that arises naturally from the ground because of the decay of radioactive elements commonly found in rocks and many types of soil. In a chain of radioactive decay, uranium produces radium, which gives off radon, which in turn produces radioactive breakdown products that are harmful if inhaled.—
Warren E. Leary
Warren E. Leary2
: so divisive or controversial as to require avoidance
He has been deemed radioactive by most charitable organizations … and organized competition, even local stuff, is largely closed off to him.—Asher Price
Asher PriceAlmost all women—and therefore men—use a form of birth control at some point in their lives, yet contraception is so politically and legally radioactive that legislators and pharmaceutical companies avoid funding it.—Karen Weise
Karen WeiseSubsequent polling data show that the quota issue is perhaps the most powerful one in our politics … A House Democratic aide says, "The quota issue is radioactive." The result has been nothing less than panic in the Democratic ranks.—Elizabeth Drew
Elizabeth Drew
radioactively
adverb
Plutonium is the only one of these transuranic elements that can exist a fair amount of time before radioactively decaying into lighter elements.
—James Kaler
James Kaler
Examples of radioactive in a Sentence
Uranium and plutonium are radioactive.
Recent Examples on the Web
The satellites caught signs of the radioactive supercharged particles and linked them to thunderstorms.
—Paul Smaglik, Discover Magazine, 3 Oct. 2024
So Peter Parker was never bitten by a radioactive spider as a teenager, Charles Xavier never set up a school for gifted young mutants, and the Fantastic Four never flew a space shuttle into a storm of cosmic radiation.
—Christian Holub, EW.com, 16 Sep. 2024
The test involves injecting a radioactive tracer into your body which helps identify whether cancer cells show up on the PET scan technology.
—Susan Russell, Health, 12 Sep. 2024
Critics said measurable radioactive materials remain in and around the Rocky Flats site and will remain for thousands of years, the media group reported.
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—Gary Stoller, Forbes, 25 Oct. 2024
See all Example Sentences for radioactive 
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Paul Smaglik, Discover Magazine, 3 Oct. 2024
So Peter Parker was never bitten by a radioactive spider as a teenager, Charles Xavier never set up a school for gifted young mutants, and the Fantastic Four never flew a space shuttle into a storm of cosmic radiation.
—Christian Holub, EW.com, 16 Sep. 2024
The test involves injecting a radioactive tracer into your body which helps identify whether cancer cells show up on the PET scan technology.
—Susan Russell, Health, 12 Sep. 2024
Critics said measurable radioactive materials remain in and around the Rocky Flats site and will remain for thousands of years, the media group reported.
Follow me on Twitter.
—Gary Stoller, Forbes, 25 Oct. 2024
See all Example Sentences for radioactive
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Dictionary Entries Near radioactive
Cite this Entry
“Radioactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radioactive. Accessed 22 Nov. 2024.
Copy CitationKids Definition
radioactive
adjective
ra·dio·ac·tive
ˌrād-ē-ō-ˈak-tiv
: of, caused by, or exhibiting radioactivity
radioactively
adverb
Medical Definition
radioactive
adjective
ra·dio·ac·tive
ˌrād-ē-ō-ˈak-tiv
: of, caused by, or exhibiting radioactivity
radioactive isotopes
radioactively
adverb
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