pernicious

C1 Topic:Describing Qualities

US /pɚˈnɪʃəs/ UK /pəˈnɪʃəs/ See IPA manual

Meanings

1

adj
having a harmful effect, especially in a gradual or subtle way

The pernicious influence of social media on mental health is a growing concern.
2

adj
causing insidious harm or ruin

The pernicious spread of misinformation can undermine public trust.

Thesaurus

Synonyms

1 adj · having a harmful effect,... harmful damaging destructive injurious detrimental

2 adj · causing insidious harm or ruin insidious malevolent malignant noxious toxic

Opposites

beneficial harmless benign wholesome

Appears in

Phrases (1)

See all

pernicious anemia
an anemia associated with impaired vitamin B12 absorption because intrinsic factor is lacking

Adjective + noun

Etymology

From Latin per- ('through') + nex/necis ('violent death') + -osus ('full of'), forming perniciosus ('destructive; deadly'); via Old French pernicieux into Middle English pernicious 'causing great harm or ruin'.

Topics

Describing Qualities Word Formation & Derivatives

External links

# pernicious

**Type:** Word
**Level:** C1
**Part of speech:** adj
**IPA (US):** /pɚˈnɪʃəs/
**IPA (UK):** /pəˈnɪʃəs/

## Meanings
1. having a harmful effect, especially in a gradual or subtle way
2. causing insidious harm or ruin

## Examples
- The pernicious influence of social media on mental health is a growing concern.
- The pernicious spread of misinformation can undermine public trust.

## Synonyms
- harmful
- damaging
- destructive
- injurious
- detrimental
- insidious
- malevolent
- malignant
- noxious
- toxic

## Antonyms
- beneficial
- harmless
- benign
- wholesome

## Etymology
From Latin per- ('through') + nex/necis ('violent death') + -osus ('full of'), forming perniciosus ('destructive; deadly'); via Old French pernicieux into Middle English pernicious 'causing great harm or ruin'.

## AI Etymology
Pernicious comes from Latin per- ('through') + nex/necis ('violent death') + -osus ('full of'), forming perniciosus ('destructive; deadly'); via Old French pernicieux into Middle English pernicious 'causing great harm or ruin'. In current use it is an adjective meaning "having a harmful effect, especially in a gradual or subtle way". That sense is explained by the older material without requiring a speculative semantic step: the inherited or borrowed base supplies the field of meaning, while the English formation fixes its modern role. The surface form is compositional: its joined elements remain visible in the modern word. The word's history is thus visible in its construction: the components remain interpretable even after the whole expression has settled into a conventional English meaning.

## Topics
- Describing Qualities
- Word Formation & Derivatives

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