Definition: Something that is dangerous or very risky can be described with the adjective perilous.
Encountered from A Literary Visitor Strolls in From the Airport by Charles Mcgrath.
“Upon arriving in New York, he walked from Kennedy Airport to the nearby Crowne Plaza Hotel, a journey more perilous than he expected, because it involved a nightmare traverse of expressways with no curbs.”
I understand this word now because usually by airports, its big highways and no sidewalks for people to walk so it would be dangerous to travel by foot.
Example: School open during extreme weather is perilous for students.