What does perilous mean?
Perilous means full of danger, risk, or the possibility of serious harm. The adjective is especially common in formal and literary English when describing journeys, expeditions, crossings, weather, decisions, or circumstances that may lead to injury, failure, or disaster. It conveys more than simply being risky: a perilous undertaking is one whose dangers are severe, immediate, or difficult to overcome. The word is often used in contexts involving physical danger, such as mountain climbing, sailing, or travel through hazardous terrain, but it can also apply to financial, professional, or personal choices. Perilous is closely related to the noun peril, which names a danger or threatening situation. Together, the two forms allow writers to describe both the quality of a hazardous situation and the danger itself. Although the word is recognized in standard British and American English, it tends to sound more literary or formal than everyday alternatives such as dangerous or hazardous.
adjectiveFull of danger or risk; dangerous or likely to cause harm. It describes situations, journeys, choices, or conditions that involve serious hazards.
- Dangerous or involving serious risk
- Extremely difficult or hazardous
"The expedition faced perilous weather as it crossed the mountains."
"The climbers took every precaution before beginning their perilous ascent."
"It would be perilous to ignore warnings about the approaching storm."
"The decision proved perilous when the financial markets suddenly collapsed."
Perilous comes from the Latin word perīculum, meaning danger: the word has carried a warning about risk for centuries.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does perilous come from?
Perilous comes from Latin perīculōsus, meaning “dangerous,” derived from perīculum, a word meaning “danger” or “risk.” The English adjective entered use through Old French perilleus, which was influenced by the Latin form. The related English noun peril comes through the same Latin word, as does the modern Latin term periculum. The word has therefore long been associated with danger, risk, and threatened harm.
Related word forms
How perilous is actually used
Perilous is formal and often literary. It is stronger than merely risky and is commonly used in descriptions of dangerous journeys, situations, decisions, and natural conditions.
Easily confused with perilous
Peril is the noun meaning danger or a serious threat, whereas perilous is the adjective describing something full of danger.