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

Such security lapses and perilous animals can lead to horrific outcomes that can create potentially significant legal and financial liabilities. —Nicole R. Kurtz, Miami Herald, 18 Dec. 2025

The fire is approaching from all sides as district officials navigate a perilous situation without a chief business officer at the helm. —Jennah Pendleton, Sacbee.com, 16 Dec. 2025

Annie, on the other hand, sets off on a perilous journey that will eventually leave her battling for her life. —Lizz Schumer, PEOPLE, 15 Dec. 2025

Those differences in Adelaide — shorter boundaries square of the wicket and perhaps less sideways movement and less bounce — are some of the reasons McCullum was in a positive mood, despite England’s perilous position. —Tim Spiers, New York Times, 14 Dec. 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