perilous

adjective

per·​il·​ous ˈper-ə-ləs 

ˈpe-rə-

: full of or involving peril

a perilous journey

perilously adverb

perilousness noun

Synonyms

• 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

The 121-year-old park in Midtown is the scene of a child's birthday that turns perilous as gusty winds send a red kite, and the little girl holding it, soaring above the Parthenon. —Bryan West, Nashville Tennessean, 18 Oct. 2025

The first time Kuhn met with the cardiothoracic surgeon, her condition was already perilous. —Calmatters, Mercury News, 17 Oct. 2025

By putting the pension reform on the chopping block, Lecornu threatens to kill off one of Macron’s main economic legacies at a time when France’s public finances are in a perilous state, leaving the president with little in the way of domestic achievements after eight years in office. —CNN Money, 16 Oct. 2025

In the 1950s and 1960s, F1 was perilous, with multiple driver deaths each season. —Eleanor Pringle, Fortune, 16 Oct. 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