Synonyms of pernicious

pernicious

adjective

pər-ˈni-shəs 

as in harmful

causing or capable of causing harm

the pernicious effects of illegal narcotics on society

Synonyms & Similar Words

• harmful
• dangerous
• detrimental
• damaging
• adverse
• bad
• poisonous
• hazardous
• deleterious
• evil
• injurious
• baneful
• infectious
• noxious
• prejudicial
• hurtful
• wicked
• mischievous
• baleful
• ill
• destructive
• hostile
• deadly
• nocuous
• venomous
• sinister
• insidious
• unsafe
• infective
• lethal
• inimical
• risky
• ominous
• unfriendly
• threatening
• pestiferous
• fatal
• malignant
• pestilential
• contagious
• perilous
• menacing
• pestilent
• unhealthful
• unwholesome
• unhealthy
• ruinous
• killer
• unsound
• nasty
• noisome
• parlous
• imperiling
• jeopardizing

Antonyms & Near Antonyms

• benign
• harmless
• beneficial
• innocuous
• innocent
• useful
• safe
• inoffensive
• advantageous
• favorable
• good
• salutary
• anodyne
• propitious
• remedial
• healthful
• healthy
• curative
• helpful
• wholesome
• palliative
• salubrious
• hurtless
• sound
• secure
• benignant
• nonpoisonous
• nonlethal
• nondestructive
• nontoxic
• nonfatal
• noninfectious
• noncorrosive
• nonpolluting
• nonvenomous

Synonym Chooser

How is the word pernicious different from other adjectives like it?

Some common synonyms of pernicious are baneful, deleterious, detrimental, and noxious. While all these words mean "exceedingly harmful," pernicious implies irreparable harm done through evil or insidious corrupting or undermining.

the claim that pornography has a pernicious effect on society

When is baneful a more appropriate choice than pernicious?

The words baneful and pernicious are synonyms, but do differ in nuance. Specifically, baneful implies injury through poisoning or destroying.

the baneful notion that discipline destroys creativity

When could deleterious be used to replace pernicious?

While in some cases nearly identical to pernicious, deleterious applies to what has an often unsuspected harmful effect.

a diet found to have deleterious effects

In what contexts can detrimental take the place of pernicious?

The meanings of detrimental and pernicious largely overlap; however, detrimental implies obvious harmfulness to something specified.

the detrimental effects of excessive drinking

When is it sensible to use noxious instead of pernicious?

While the synonyms noxious and pernicious are close in meaning, noxious applies to what is both offensive and injurious to the health of a body or mind.

noxious chemical fumes

Example Sentences

Recent Examples of pernicious

Nine crucial years of expansion and solidification of the pernicious institution went by, speeding the nation’s road toward a grinding war. — Literary Hub, 3 June 2026

Microplastics are tiny fragments, that can be as small as 1/25,000th of an inch (1 micrometer) and are a pernicious part of the plastic pollution crisis. — Laura Paddison, CNN Money, 29 Apr. 2026

And that’s not all — Yeon’s new film about the pernicious undead has set its North American theatrical release date. — Abid Rahman, HollywoodReporter, 14 Apr. 2026

That may sound like a smart countermeasure to a pernicious tech shortcut. — Nathan Agranovsky, Washington Post, 13 Apr. 2026