1 likely to harm or kill someone, or to damage or destroy something
a dangerous dog
a dangerous stretch of road
Air pollution has reached dangerous levels in some cities.
highly dangerous: an exciting but highly dangerous sport
potentially dangerous: Children are taught to avoid potentially dangerous situations.
dangerous to: It is not yet known whether these chemicals are dangerous to humans.
it is dangerous (for someone) to do something: It’s dangerous to walk around here on your own at night.
Synonyms and related words