say it: ray-dee-oh-AK-tiv
radioactive is an adjective meaning "exhibiting or caused by radioactivity". It carries one recorded sense.
exhibiting or caused by radioactivity
“radioactive isotope”
“radioactive decay”
“radioactive fallout”
Definitions, synonyms and semantic relations for radioactive come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.