perilous

1 of 2

adjective

per·​il·​ous ˈper-ə-ləs 

ˈpe-rə-

: full of or involving peril

a perilous journey

perilously adverb

perilousness noun

perilousness

2 of 2

noun

per·​il·​ous·​ness

plural -es

: the quality or state of being perilous

Synonyms of perilous

Adjective

• 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

Adjective

a perilous journey across the mountains

a perilous journey through hostile territory

Recent Examples on the Web

Adjective

America’s next president, and the class of senators elected this November, seem all but guaranteed to face the politically perilous task of addressing Social Security’s imminent insolvency before the end of their term. —Ben Ritz, Forbes.com, 11 June 2026

Leo is spending the final two days of his weeklong trip to Spain in the Canary Islands, a Spanish archipelago closer to Africa than the Iberian Peninsula and a key point of entry for migrants who make the perilous Atlantic crossing from West Africa. —Nicole Winfield, Los Angeles Times, 11 June 2026

Is the trek as perilous as some have led us to believe? —Sean Gregory, Time, 11 June 2026

Francis had visited Lampedusa in 2013, on his first trip outside Rome, and tossed a wreath into the Mediterranean in honor of the thousands of migrants who died in the perilous crossing. —ABC News, 10 June 2026

Word History

Etymology

Adjective

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

Adjective

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