perilous

adjective

per·​il·​ous ˈper-ə-ləs How to pronounce perilous (audio)
ˈpe-rə-
Synonyms of perilous
: full of or involving peril
a perilous journey
perilously adverb
perilousness noun

Synonyms of perilous

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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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Candidate messaging Candidates could consider moderating their message to attract orphaned voters, though that can be perilous. — Kevin Rector, Los Angeles Times, 3 Aug. 2026 Originally famed for the company’s organs that swelled Detroit theaters and churches, the situation became perilous after Wurlitzer and the remaining tenants all left by 1982. — Condé Nast, Condé Nast Traveler, 1 Aug. 2026 The story of an experienced hiker on a perilous stretch of the Appalachian Trail who gets lost in the Maine woods. — The Week Us, TheWeek, 31 July 2026 In this context, replicating reputation management by political methods could prove perilous. — Jon Michail, Forbes.com, 29 July 2026 See All Example Sentences for perilous

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

Time Traveler
The first known use of perilous was in the 14th century

Rhymes for perilous

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Browse Nearby Words

perilless
perilous
perilously
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Cite this Entry

“Perilous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/perilous. Accessed 7 Aug. 2026.

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Kids Definition

perilous

adjective
per·​il·​ous ˈper-ə-ləs How to pronounce perilous (audio)
: full of or involving peril
perilously adverb
perilousness noun

More from Merriam-Webster on perilous

Nglish: Translation of perilous for Spanish Speakers

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