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

Understanding the gravity of a red flag warning and adhering to these precautions is pivotal in mitigating the risk of wildfires during these perilous conditions. —Kansas City Star Weather Bot, Kansas City Star, 27 Mar. 2026

Experts are warning that the unprecedented heat wave that has roasted the West during the past two weeks has also set the stage for a potentially perilous wildfire season. —Andrew Freedman, CNN Money, 27 Mar. 2026

The health care impact would come as some hospitals in the region face perilous conditions, according to the World Health Organization (WHO). —Max Zahn, ABC News, 27 Mar. 2026

There is little time to reflect with such a perilous path ahead, but on Monday, there was the first sense of finality. —Marisa Ingemi, Los Angeles Times, 24 Mar. 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