Synonyms of deleterious

deleterious

adjective

ˌde-lə-ˈtir-ē-əs 

as in harmful

causing or capable of causing harm

nicotine has long been recognized as a deleterious substance

Synonyms & Similar Words

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

Antonyms & Near Antonyms

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

Synonym Chooser

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

Some common synonyms of deleterious are baneful, detrimental, noxious, and pernicious. While all these words mean "exceedingly harmful," deleterious applies to what has an often unsuspected harmful effect.

a diet found to have deleterious effects

When is baneful a more appropriate choice than deleterious?

The synonyms baneful and deleterious are sometimes interchangeable, but baneful implies injury through poisoning or destroying.

the baneful notion that discipline destroys creativity

When would detrimental be a good substitute for deleterious?

The words detrimental and deleterious are synonyms, but do differ in nuance. Specifically, detrimental implies obvious harmfulness to something specified.

the detrimental effects of excessive drinking

When can noxious be used instead of deleterious?

The meanings of noxious and deleterious largely overlap; however, noxious applies to what is both offensive and injurious to the health of a body or mind.

noxious chemical fumes

Where would pernicious be a reasonable alternative to deleterious?

The words pernicious and deleterious can be used in similar contexts, but pernicious implies irreparable harm done through evil or insidious corrupting or undermining.

the claim that pornography has a pernicious effect on society

Example Sentences

Recent Examples of deleterious

There are already many common-sense proposals to fix the influence and deleterious effects of social media on society as a whole. — Linh Tat, Oc Register, 5 May 2026

The guidance has evolved over the years, but the most recent studies have found that any level of drinking can have deleterious effects. — Lois K. Solomon, Sun Sentinel, 22 Apr. 2026

Setting yourself up to overcome its deleterious effects on your money should be one of your top priorities, says Boneparth. — Ryan Ermey, CNBC, 1 Apr. 2026

Alcohol, even marijuana, even light marijuana use, can have a deleterious effect on the development of a young brain. — Stephanie Nolasco, FOXNews.com, 29 Mar. 2026

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