ˈdānj(ə)rəs adjective
Etymology: Middle English daungerous haughty, trouble-making, hard to please, from Old French dangereus trouble-making, hard to please, from dangier + -eus -ous
1. : exposing to danger : involving risk : demanding caution or care as extremely unsafe : hazardous , perilous
a little learning is a dangerous thing — Alexander Pope
a dangerous climb
dangerous occupations
a dangerous crossing
2. : able or likely to inflict injury : causing or threatening harm
a dangerous lunatic
an animal dangerous when wounded
3. now dialect : gravely ill : in critical condition
he's in bed but he's not dangerous
Synonyms:
hazardous , precarious , perilous , risky : dangerous applies to persons or things to be avoided or treated carefully as generally unsafe and likely to cause or be attended by danger
a wide circuit must be made, to avoid a fierce and dangerous tribe called Snake Indians — Francis Parkman
the most dangerous waters in the world, the fog-shrouded, berg-haunted Grand Banks, with their swift currents and steep, short seas — American Guide Series: Massachusetts
hazardous may imply greater operation of chance than dangerous; it is used in reference to situations involving great or continuous risk
life consists largely of hazardous leaps in the dark — M.R.Cohen
the hazardous game of secret service in enemy country — Alexander Forbes
Established with the meaning of insecure or uncertain, precarious often adds the implication of attendant dangers
the unorganised mass of London dock laborers who struggled with each other for precarious jobs at the dockyard gates — G.M.Trevelyan
the British army, its communications thus rendered precarious, was forced to retreat — Allan Nevins & H.S.Commager
perilous suggests imminent danger
thousands of ships and planes guarding the long, perilous sea lanes — F.D.Roosevelt
burglars who have done a good … business are, as a rule, only too glad to enjoy the proceeds in peace and quiet without embarking on another perilous undertaking — A. Conan Doyle
risky often joins to this suggestion the notion that the danger or risk has been realized in advance and willingly accepted
the control of our universities by propertied interests makes a free and radical inquiry into social affairs a risky business for any professor — M.R.Cohen
so risky was travel that the Indiana legislature specifically permitted travelers to carry concealed weapons of any kind — Carl Sandburg