1. emitting radiation: describes a substance such as uranium or plutonium that emits energy in the form of streams of particles, owing to the decaying of its unstable atoms. This energy can be damaging or fatal to the health of people exposed to it.
2. physics of or using radioactive substances: relating to or making use of radioactive substances or the radiation they emit
3. highly controversial: so highly controversial that people tend to avoid the person or issue in question The topic of campaign finance reform is radioactive in many constituencies.
