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

Williams heads up the Rory Peck Trust, which provides funds and training to aid the security of freelance journalists who are reporting in perilous zones. — David Folkenflik, NPR, 4 Oct. 2026

Alas, for an increasing share of the population, stretching to buy a home is a perilous financial move. — The Editorial Board, Chicago Tribune, 2 Oct. 2026

The shadow that hangs over the entire series, though, is the perilous future of the church. — John Blake, CNN Money, 1 Oct. 2026

Passengers and other pilots aboard helped restrain the co-pilot and land the Boeing 737 in Saudi Arabia after a perilous plunge that tore away its rudder. — Melanie Lidman, Los Angeles Times, 1 Oct. 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