dangerous

What it means

1. Full of danger.

   Railway crossings without gates are highly dangerous.

   2 more examples

   [I]t is not fair of you to bring against mankind double weapons! Dangerous enough you are as woman alone, without bringing to your aid those gifts of mind suited to problems which men have been accustomed to arrogate to themselves.

   1910, Emerson Hough, chapter I, in The Purchase Price: Or The Cause of Compromise, Indianapolis, Ind.: The Bobbs-Merrill Company, →OCLC

   Young Indians looking for work opportunities have made up a sizeable portion of undocumented migrants in the US, many after making the dangerous trek through Latin America to reach the US southern border.

   2025 February 7, Esha Mitra, Aishwarya S Iyer and Ross Adkin, “‘Treated like criminals’: Shackling of Indians aboard 40-hour migrant flight sparks new outrage against Trump”, in CNN

   Synonyms: hazardous, perilous, risky, unsafe · Antonyms: safe

2. Causing danger; ready to do harm or injury.

   If they incline to think you dangerous, / They have their knaviſh Arts to make you ſo.

   1696, Tho[mas] Southerne, Oroonoko: A Tragedy […], London: […] H[enry] Playford […]; B[enjamin] Tooke […]; [a]nd S. Buckley […], →OCLC, act III, scene ii, page 41

   1 more example

   And the Duke thought: The truth could be worse than he imagines, but even dangerous facts are valuable if you’ve been trained to deal with them. And there’s one place where nothing has been spared for my son—dealing with dangerous facts.

   1965 October 1, Frank Herbert, “Book I: Dune”, in Dune, Philadelphia, Pa.: Chilton Book Company; [Toronto], Ont.: Thomas Nelson & Sons, →OCLC, page 42

3. colloquialdatedIn a condition of danger, as from illness; threatened with death.

In a sentence

Railway crossings without gates are highly dangerous.

Where it comes from

1. Old Frenchdangereus“threatening, difficult”
2. Anglo-Norman[Term?]
3. Middle Englishdaungerous“difficult, severe, domineering, arrogant, fraught with danger”
4. Englishdangerous

From Middle English daungerous (“difficult, severe, domineering, arrogant, fraught with danger”), dangerous, from Anglo-Norman [Term?], from Old French dangereus (“threatening, difficult”), from dangier. Equivalent to danger + -ous. Displaced native Old English frēcne.