perilous

adjective

per·​il·​ous ˈper-ə-ləs 

ˈpe-rə-

: full of or involving peril

a perilous journey

perilously adverb

perilousness noun

Synonyms

• dangerous
• grave
• grievous
• hazardous
• jeopardizing
• menacing
• parlous
• risky
• serious
• threatening
• unhealthy
• unsafe
• venturesome

Choose the Right Synonym for perilous

dangerous, hazardous, precarious, perilous, risky mean bringing or involving the chance of loss or injury.

dangerous applies to something that may cause harm or loss unless dealt with carefully.

soldiers on a dangerous mission

hazardous implies great and continuous risk of harm or failure.

claims that smoking is hazardous to your health

precarious suggests both insecurity and uncertainty.

earned a precarious living by gambling

perilous strongly implies the immediacy of danger.

perilous mountain roads

risky often applies to a known and accepted danger.

shied away from risky investments

Examples of perilous in a Sentence

a perilous journey across the mountains

a perilous journey through hostile territory

Recent Examples on the Web

The deepest fear: Just four years after the chaotic withdrawal from Afghanistan ended America's longest war, the United States is now enmeshed in another war in a volatile region, with perilous and uncertain consequences. —Susan Page, USA Today, 23 June 2025

The Darién Gap, long a perilous route for millions of migrants traveling north toward the United States, has also become a pathway for the northward spread of the New World screwworm—a parasitic fly now challenging decades of containment efforts. —Jesus Mesa, MSNBC Newsweek, 23 June 2025

Understanding the gravity of a red flag warning and adhering to these precautions is paramount in averting wildfires during these perilous conditions. —Ca Weather Bot, Sacbee.com, 22 June 2025

In the post-pandemic world, trading is popular and perilous. —Daniel Schlaepfer, Forbes.com, 19 June 2025

Word History

Etymology

Middle English perilous, perelous, borrowed from Anglo-French perilleus, perillous, going back to Latin perīculōsus, from perīculum "test, risk, peril entry 1" + -ōsus -ous

First Known Use

14th century, in the meaning defined above

Rhymes for perilous

• carolus
• garrulous
• querulous
• puberulous

Kids Definition

perilous

adjective

per·​il·​ous ˈper-ə-ləs 

: full of or involving peril

perilously adverb

perilousness noun