perilous

adjective

per·​il·​ous ˈper-ə-ləs 

ˈpe-rə-

: full of or involving peril

a perilous journey

perilously adverb

perilousness noun

Synonyms

• dangerous
• grave
• grievous
• hazardous
• jeopardizing
• menacing
• parlous
• risky
• serious
• threatening
• unhealthy
• unsafe
• venturesome

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

But a downside surprise could be perilous considering the recent spate of bad economic news and the prevailing angst over the way President Donald Trump is implementing tariffs against U.S. trading partners. —Jeff Cox, CNBC, 1 May 2025

It’s now become emblematic of the fight to protect trans women during a politically perilous time. —Denny, Them., 30 Apr. 2025

For those of us who are serious chocolate addicts, there are two times every year — Easter and Halloween — that are positively perilous. —Inga, San Diego Union-Tribune, 28 Apr. 2025

The dinner comes at a perilous time for the association, having lost control of the White House press pool − the group of reporters who fly on Air Force One and cover the president in tight spaces such as the Oval Office. —James Powel, USA Today, 27 Apr. 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