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

The future is looking pretty perilous, and so people turn to spiritual matters. — Claire Hoffman, Rolling Stone, 21 Sep. 2026

Animals that bridge the human world and the wild can be uniquely perilous to human health, Dan Werb writes. — David A. Graham, The Atlantic, 18 Sep. 2026

What follows is a modern picaresque journey, in which a clever underdog has to rely on her wit and wiles to survive a corrupt and perilous world. — Theater Critic, Los Angeles Times, 17 Sep. 2026

Nesting is always perilous, but the moment when the male and female trade places is especially so, as the incubating bird’s movement may catch the attention of a predator. — Rivka Galchen, New Yorker, 14 Sep. 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