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

More than two months into the war in Iran, navigation through the Strait of Hormuz – the key waterway through which more than a third of the international trade in oil and gas passes – remains perilous and uncertain. —Vivek Krishnamurthy, The Conversation, 5 May 2026

My journey nonetheless felt perilous. —Jennifer Wilson, New Yorker, 4 May 2026

Far from benign, some experts say the videos can skew how people view and even interact with wildlife — potentially leading to perilous encounters. —Lila Seidman, Los Angeles Times, 2 May 2026

It's become a more perilous occupation to be President of the United States, or a congressional leader, or to be a state legislator in Minnesota, or to be the spouse of a former House speaker. —Dana Taylor, USA Today, 28 Apr. 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