English Lexicon

Deleterious

/ˌdɛl.əˈtɪə.ri.əs/
adjectiveCEFR C2 (Proficient)Top #8500 frequency
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Comprehensive Definitions & Senses

2 senses
As adjective
  1. 1

    Causing harm or damage, often in a subtle or unexpected way.

    "The committee warned about the deleterious effects of industrial pollution on local wildlife."
  2. 2

    Harmful to living things; noxious or injurious.

    "Exposure to high levels of radiation can have deleterious consequences for human health."

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Antonyms & Contrasting Words (1)

Linguistic Origin & Historical Etymology

Derived from the Greek word 'dēleitērios', meaning hurtful or noxious, stemming from 'deleis' (hurt or mischief). It entered Late Latin as 'deleterius' and eventually passed into English in the mid-17th century to describe things causing harm or damage.

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