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

So when and why did humans fall prey to such a pernicious threat? —Andrew Paul, Popular Science, 26 Feb. 2026

While critiques of America’s pernicious gambling culture and hypocritical application to athletes never overwhelm the story (or even develop beyond a few jabs per episode), Season 1 lays the groundwork to delve deeper later on while hitting plenty of targets here and now. —Ben Travers, IndieWire, 23 Feb. 2026

Secretary of State Marco Rubio, whose parents left Cuba a few years before Fidel Castro took power, has eyed the regime in Havana as one of the world’s most pernicious, inhumane and troublesome. —Daniel Depetris, Chicago Tribune, 3 Feb. 2026

America’s pernicious relationship with Haiti comes to a head once more this week. —Ruth Jean-Marie, Time, 3 Feb. 2026