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, of course, follows Greek King of Ithaca Odysseus’ perilous, decades-long trek home to Queen Penelope (Anne Hathaway) and their son, Prince Telemachus (Tom Holland) follow his army’s victory during the Trojan War. — Tim Lammers, Forbes.com, 21 July 2026

Labor conditions, the group says, have grown perilous due to extreme heat—both in the area in general and within the museums themselves—and strike action being taken is now a possibility. — News Desk, Artforum, 20 July 2026

As the title suggests, The Odyssey is about Odysseus (Matt Damon) and his perilous journey home after the Trojan War. — Britt Hayes, Entertainment Weekly, 20 July 2026

Heading to the beach to get a break from the heat could be perilous. — Los Angeles Times, 20 July 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