perilous

adjective

per·​il·​ous ˈper-ə-ləs 

ˈpe-rə-

: full of or involving peril

a perilous journey

perilously adverb

perilousness noun

Synonyms

• dangerous
• hazardous
• risky
• serious

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

This context and backdrop adorns the film with considerable energy, various colorful personalities and smartly edited archival news footage that deepens our understanding of the perilous stakes. —Tomris Laffly, Variety, 28 Sep. 2025

My hope was that exploring the past in a nuanced way might offer insight into our surprising and perilous present. —Cressida Leyshon, New Yorker, 28 Sep. 2025

The season finale of House of Guinness opens with Patrick Cochrane — the Fenian Brotherhood leader who Edward had banished to New York — secretly returning to Ireland, with both an axe to grind against the Guinnesses and a perilous political mission to carry out. —Lynsey Eidell, PEOPLE, 27 Sep. 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, 26 Sep. 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