What does pernicious mean?
Pernicious is an adjective describing something actively harmful, especially an influence, practice, or idea that causes damage in a subtle or morally corrupting way. The word is often used for political dishonesty, manipulative propaganda, destructive habits, or social conditions that undermine wellbeing. It can also mean deadly or severely damaging in more direct contexts, such as a pernicious poison or disease. Because 'pernicious' suggests more than ordinary harm, it often conveys disapproval and a sense that the negative effect is serious, persistent, or morally troubling. The related adverb is 'perniciously' and the noun is 'perniciousness.' The word is especially common in formal writing and discussion, although it is understood in general English throughout Britain and the United States.
adjectiveHarmful, damaging, or destructive, especially in a moral, social, or political sense. It can also describe something that causes death or serious harm.
- Causing serious harm, especially through a subtle or morally corrupting influence.
- Extremely harmful, destructive, or deadly.
"The newspaper warned that misinformation could have a pernicious influence on democratic institutions."
"The policy was condemned as a pernicious attempt to undermine public trust."
"The poison had a pernicious effect on the nervous system."
A pernicious idea is not merely unpleasant: it can quietly damage people, institutions, or public life.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does pernicious come from?
Pernicious entered English in the late Middle English period from Latin 'perniciosus,' meaning destructive or harmful. The Latin adjective was related to 'pernicies,' meaning ruin, loss, or destruction, which is connected with the Latin root for killing. Its modern sense developed from the idea of harm that is especially severe or corrupting, and the word is now used for both moral and physical damage.
Related word forms
How pernicious is actually used
Usually used in formal or serious contexts. It is stronger and more often more figurative than 'harmful,' and it frequently carries a moral or social judgment.