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

This narrative series tells Samia’s extraordinary story of resilience, ambition, and the perilous intersection of sport, war, and migration. —Ryan Lattanzio, IndieWire, 21 Apr. 2026

More than 6,500 Rohingya attempted perilous sea crossings that year, with one in seven reported missing or dead, the UNHCR said in a statement from Geneva. —ABC News, 17 Apr. 2026

Matt Damon stars Odysseus, the king of Ithaca, and chronicles his long and perilous return home after the Trojan War. —Rebecca Rubin, Variety, 15 Apr. 2026

The minutes-long standstill forced several people into the street; many more, including my husband and his cane, engaged in a potentially perilous stutter-step around the two knee-high, randomly moving yet noncommunicative vehicles. —Culture Critic, Los Angeles Times, 14 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