1. (n.)blue the pure color of a clear sky; the primary color between green and violet in the visible spectrum, an effect of light with a wavelength between 450 and 500 nm.
20. blue blue in the face, at an extreme point of frustration, irritation, discouragement, etc.: to argue till one is blue in the face.
21. blue out of the blue, suddenly and unexpectedly.
Etymology: (1250–1300; ME blewe < AF blew, bl(i)u blue, livid, OF blo, blau < Gmc *blæmacr;waz)
Definition of 'blue'
Princeton's WordNet
1. (noun)blue, blueness blue color or pigment; resembling the color of the clear sky in the daytime "he had eyes of bright blue"
2. (noun)blue blue clothing "she was wearing blue"
3. (noun)blue any organization or party whose uniforms or badges are blue "the Union army was a vast blue"
4. (noun)blue sky, blue, blue air, wild blue yonder the sky as viewed during daylight "he shot an arrow into the blue"
5. (noun)bluing, blueing, blue used to whiten laundry or hair or give it a bluish tinge
6. (noun)amobarbital sodium, blue, blue angel, blue devil, Amytal the sodium salt of amobarbital that is used as a barbiturate; used as a sedative and a hypnotic
7. (adj)blue any of numerous small butterflies of the family Lycaenidae
8. (adj)blue, bluish, blueish of the color intermediate between green and violet; having a color similar to that of a clear unclouded sky "October's bright blue weather"- Helen Hunt Jackson; "a blue flame"; "blue haze of tobacco smoke"
9. (adj)blue used to signify the Union forces in the American Civil War (who wore blue uniforms) "a ragged blue line"
10. (adj)gloomy, grim, blue, depressed, dispirited, down(p), downcast, downhearted, down in the mouth, low, low-spirited filled with melancholy and despondency "gloomy at the thought of what he had to face"; "gloomy predictions"; "a gloomy silence"; "took a grim view of the economy"; "the darkening mood"; "lonely and blue in a strange city"; "depressed by the loss of his job"; "a dispirited and resigned expression on her face"; "downcast after his defeat"; "feeling discouraged and downhearted"
11. (adj)blasphemous, blue, profane characterized by profanity or cursing "foul-mouthed and blasphemous"; "blue language"; "profane words"
12. (adj)blue, gamy, gamey, juicy, naughty, racy, risque, spicy suggestive of sexual impropriety "a blue movie"; "blue jokes"; "he skips asterisks and gives you the gamy details"; "a juicy scandal"; "a naughty wink"; "naughty words"; "racy anecdotes"; "a risque story"; "spicy gossip"
13. (adj)aristocratic, aristocratical, blue, blue-blooded, gentle, patrician belonging to or characteristic of the nobility or aristocracy "an aristocratic family"; "aristocratic Bostonians"; "aristocratic government"; "a blue family"; "blue blood"; "the blue-blooded aristocracy"; "of gentle blood"; "patrician landholders of the American South"; "aristocratic bearing"; "aristocratic features"; "patrician tastes"
14. (adj)blue(a), puritanic, puritanical morally rigorous and strict "the puritan work ethic"; "puritanic distaste for alcohol"; "she was anything but puritanical in her behavior"
15. (verb)blue, dark, dingy, disconsolate, dismal, gloomy, grim, sorry, drab, drear, dreary causing dejection "a blue day"; "the dark days of the war"; "a week of rainy depressing weather"; "a disconsolate winter landscape"; "the first dismal dispiriting days of November"; "a dark gloomy day"; "grim rainy weather"
1. (adjective)blue being the color of the sky blue eyes/jeans
2. blue sad I was feeling blue.
3. (noun)blue the color of the sky a dark/light blue; a room done in blues and greens
4. blue out of the blue unexpectedly Her decision came out of the blue.
Definition of 'blue'
Webster Dictionary
1. (noun)blue one of the seven colors into which the rays of light divide themselves, when refracted through a glass prism; the color of the clear sky, or a color resembling that, whether lighter or darker; a pigment having such color. Sometimes, poetically, the sky
3. blue having the color of the clear sky, or a hue resembling it, whether lighter or darker; as, the deep, blue sea; as blue as a sapphire; blue violets
4. blue pale, without redness or glare, -- said of a flame; hence, of the color of burning brimstone, betokening the presence of ghosts or devils; as, the candleburns blue; the air was blue with oaths
5. blue low in spirits; melancholy; as, to feelblue
6. blue suited to produce low spirits; gloomy in prospect; as, thongs looked blue
7. blue severe or over strict in morals; gloom; as, blue and sour religionists; suiting one who is over strict in morals; inculcating an impracticable, severe, or gloomy mortality; as, bluelaws
Definitions of blue 
Afrikaans: blou
Arabic: أزْرَق
Bulgarian: син
Brazilian: azul
Czech: modrý
German: blau
Danish: blå
Greek: μπλε, γαλάζιος
Spanish: azul
Estonian: sinine
Farsi: آبی
Finnish: sininen
French: bleu
Hebrew: כָּחֹל @@@כָּחוֹל$$$
Hindi: नीला
Croatian: plavo
Hungarian: kék
Indonesian: biru
Icelandic: blár litur
Italian: blu, azzurro
Japanese: 青い
Korean: 파란색의
Lithuanian: mėlynas
Latvian: zils
Malay: biru
Dutch: blauw
Norwegian: blå(farget)
Polish: niebieski
Persian: آبی
Pashto: اوبیز
Portuguese: azul
Romanian: albastru
Russian: голубой, синий
Slovak: modrý
Slovenian: moder
Serbian: plav
Swedish: blå
Thai: ฟ้า; น้ำเงิน
Turkish: mavi
Taiwanese: 天藍色的
Ukrainian: синій; блакитний
Urdu: نیلا
Vietnamese: xanh
Chinese: 天蓝色的
