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

The first season traces Ellie and Joel’s perilous journey, punctuated by attacks by the infected, the depredations of groups of raiders, and betrayals galore by would-be allies. —Michael M. Rosen, The Washington Examiner, 30 May 2025

One brother, guided by moral duty, convinces the other to help the mother and join a perilous investigation to find the child. —Naman Ramachandran, Variety, 26 May 2025

There are a couple of perilous situations where Nani and her neighbor/friend David (Kaipo Dudoit) have to save Lilo and the alien from drowning. —Brian Truitt, USA Today, 23 May 2025

Six-part series Guardians, which highlights the perilous and crucial work of rangers working to keep wildlife safe across the world, is the culmination of 18 months of work for the prince and his team. —Simon Perry, People.com, 22 May 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