radioactive

radioactive — adjective

1. Describes a substance that gives off a form of energy called radiation, created

1.形容詞B2
釋義

Describes a substance that gives off a form of energy called radiation, created when the centre of an atom breaks apart. This process can be harmful to living cells and is also used in medicine and power generation.

例句

Jisoo learned at school that radioactive elements slowly change into other elements over time.

radioactive + noun (element, waste, material)

The workers sealed the radioactive waste inside thick concrete barrels.

同義詞
  • irradiated

    refers to something that has been exposed to radiation, not something that produces it

  • nuclear

    relates to atomic nuclei more broadly; covers power, weapons, and medicine beyond just radiation emission

反義詞

文法句型

radioactive + noun (waste, material, element, isotope)

用法筆記

Not gradable — a substance is either radioactive or it is not. Common collocations in news reports include 'radioactive waste,' 'radioactive contamination,' and 'radioactive material.'

常見錯誤

❌The water became radioactive after the factory dumped chemicals in it.
✅The water became contaminated after the factory dumped chemicals in it.
💡Radioactivity comes from atoms breaking apart, not from chemical pollution. Not all dangerous substances are radioactive.

2. Used informally to describe a subject, issue, or person that has become so contr

2.形容詞C1
釋義

Used informally to describe a subject, issue, or person that has become so controversial or damaging that people avoid talking about it or getting involved with it.

例句

The proposed tax changes became a radioactive issue that no politician wanted to touch.

figurative: radioactive issue / topic / subject

Kwame warned his colleagues that the merger was a radioactive topic in the boardroom.

同義詞
  • toxic

    similar metaphorical meaning of being damaging to associate with, but 'toxic' is broader in its figurative uses

  • taboo

    emphasises social prohibition rather than danger; often stronger

  • untouchable

    suggests that the issue is so bad that people refuse to be associated with it

反義詞
  • safe

    an issue or topic that people are comfortable discussing

  • neutral

    not controversial or likely to cause a reaction

文法句型

radioactive + noun (issue, topic, subject, name)

用法筆記

This is a metaphorical, informal extension of the literal meaning, most common in political and business journalism. Unlike the literal sense, it can occasionally appear in comparative forms (e.g., 'more radioactive than'), though this is rare.

常見錯誤

❌The chemical spill was radioactive for the environment.
✅The CEO's reputation became radioactive after the scandal broke.
💡In the figurative sense, 'radioactive' refers to social or political danger, not physical toxicity.