Synonyms of perilous

perilous

adjective

ˈper-ə-ləs 

as in dangerous

involving potential loss or injury

a perilous journey through hostile territory

Synonyms & Similar Words

• dangerous
• hazardous
• risky
• serious
• precarious
• unsafe
• treacherous
• menacing
• threatening
• unhealthy
• grave
• parlous
• grievous
• venturesome
• uncertain
• fatal
• random
• jeopardizing
• unpleasant
• destructive
• detrimental
• harmful
• deadly
• adverse
• bad
• dicey
• lethal
• sickening
• haphazard
• insecure
• chance
• murderous
• injurious
• distressing
• ugly
• pernicious
• fell
• fateful
• dire
• nasty
• malignant
• deleterious
• wicked
• baneful
• evil
• ultrahazardous
• noxious
• inimical
• killer
• hurtful
• mortal
• ill
• baleful
• deathly
• pestilent

Antonyms & Near Antonyms

• safe
• harmless
• innocuous
• innocent
• beneficial
• advantageous
• nonhazardous
• nonthreatening
• good
• unthreatening
• ultrasafe

Synonym Chooser

How is the word perilous distinct from other similar adjectives?

Some common synonyms of perilous are dangerous, hazardous, precarious, and risky. While all these words mean "bringing or involving the chance of loss or injury," perilous strongly implies the immediacy of danger.

perilous mountain roads

When might dangerous be a better fit than perilous?

The words dangerous and perilous are synonyms, but do differ in nuance. Specifically, dangerous applies to something that may cause harm or loss unless dealt with carefully.

soldiers on a dangerous mission

When is it sensible to use hazardous instead of perilous?

The synonyms hazardous and perilous are sometimes interchangeable, but hazardous implies great and continuous risk of harm or failure.

claims that smoking is hazardous to your health

When can precarious be used instead of perilous?

While in some cases nearly identical to perilous, precarious suggests both insecurity and uncertainty.

earned a precarious living by gambling

When would risky be a good substitute for perilous?

In some situations, the words risky and perilous are roughly equivalent. However, risky often applies to a known and accepted danger.

shied away from risky investments

Example Sentences

Recent Examples of perilous

Adding to the urgency is a so-far historically dry winter at a legally perilous time. —Brandon Loomis, AZCentral.com, 13 Feb. 2026

The horror-Western follows a settler family on a perilous journey across the Kalahari Desert in the mid-1800s. —Jesse Whittock, Deadline, 10 Feb. 2026

The surrounding seas are perilous, and traveling there is difficult even with modern boats. —K. R. Callaway, Scientific American, 9 Feb. 2026

Those numbers represent politically perilous territory for the GOP. —Craig Gilbert, jsonline.com, 9 Feb. 2026