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

Severe weather cut power to nearly 1 million customers in the Midwest as perilous thunderstorms and extreme wind gusts pummeled the region Tuesday. — CBS News, 11 Aug. 2026

Severe weather cut power Tuesday in the Chicago area and northwestern Indiana as perilous storms pummeled the region, darkening the sky and carrying extreme wind gusts across state lines. — ABC News, 11 Aug. 2026

But Curious George, whose first standalone book follows a voyage from an African jungle to a New York City zoo, would not become the hero of his own story until the Reys underwent a perilous journey of their own. — Encyclopedia Britannica, 7 Aug. 2026

The decline of these vast reservoirs underscores the perilous situation of the Colorado River. — Laura Paddison, CNN Money, 7 Aug. 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