noun
radioactive
Used as a noun or in compounds to describe substances, materials, or phenomena that emit radiation. Common in scientific and news contexts.
放射性廃棄物の処理は重要な課題だ。
The disposal of radioactive waste is an important issue.
この地域では放射性物質
Radioactive materials were detected in this area.
Compound of 放射 (radiation) + 性 (nature, property), literally 'radiation-property'. The term is a modern scientific coinage.