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English definition of “radioactive”

radioactive

adjective     /ˌreɪ.di.əʊˈæk.tɪv/ US  /-oʊ-/
having or producing the energy that comes from the breaking up of atoms : Uranium is a radioactive material . radioactive waste Radiation and radioactivity
(Definition of radioactive adjective from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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