perilous

adjective

per·​il·​ous ˈper-ə-ləs 

ˈpe-rə-

: full of or involving peril

a perilous journey

perilously adverb

perilousness noun

Synonyms of perilous

• 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

The Odyssey is slated to premiere on July 17, 2026, and is an adaptation of Homer’s epic poem about Odysseus, King of Ithaca, and his perilous journey home after the Trojan War. —Armando Tinoco, Deadline, 13 May 2026

Understanding the gravity of a red flag warning and adhering to these precautions is pivotal in mitigating the risk of wildfires during these perilous conditions. —Ca Weather Bot, Sacbee.com, 12 May 2026

As Seth seethes about his separation from his home country (and the family fortune), Arias interweaves a backstory involving assassination, undisclosed parentage and (as the title suggests) the perilous creatures slithering across the landscape. —Michael Schaub, Los Angeles Times, 12 May 2026

The Libyan coast is one of the main departure points for migrants crossing the Mediterranean Sea from North Africa in small boats, with thousands dying during the perilous journey. —ABC News, 11 May 2026

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