adj., n., & v.
adj. 1 having a colour like that of a clear sky. 2 sad, depressed; (of a state of affairs) gloomy, dismal (feel blue; blue times). 3 indecent, pornographic (a blue film). 4 with bluish skin through cold, fear, anger, etc. 5 Brit. politically conservative. 6 having blue as a distinguishing colour (blue jay).
n. 1 a blue colour or pigment. 2 blue clothes or material (dressed in blue). 3 Brit. a a person who has represented a university in a sport, esp. Oxford or Cambridge. b this distinction. 4 Brit. a supporter of the Conservative party. 5 any of various small blue-coloured butterflies of the family Lycaenidae. 6 blue powder used to whiten laundry. 7 Austral. sl. a an argument or row. b (as a nickname) a red-headed person. 8 a blue ball, piece, etc. in a game or sport. 9 (prec. by the) the clear sky.
v.tr. (blues, blued, bluing or blueing) 1 make blue. 2 treat with laundering blue. blue baby a baby with a blue complexion from lack of oxygen in the blood due to a congenital defect of the heart or great vessels. blue bag a lawyer's brief-bag. blue blood noble birth. blue-blooded of noble birth. Blue Book a report issued by Parliament or the Privy Council. blue cheese cheese produced with veins of blue mould, e.g. Stilton and Danish Blue. blue-chip (attrib.) of shares of reliable investment, though less secure than gilt-edged stock. blue-collar (attrib.) of manual or unskilled work. blue dahlia something rare or impossible. blue ensign see ENSIGN. blue-eyed boy esp. Brit. colloq. usu. derog. a favoured person; a favourite. blue funk esp. Brit. colloq. a state of great terror or panic. blue-green alga = CYANOBACTERIUM. blue ground = KIMBERLITE. blue in the face in a state of extreme anger or exasperation. blue metal broken blue stone used for road-making. blue mould a bluish fungus growing on food and other organic matter. blue-pencil (-pencilled, -pencilling; US -penciled, -penciling) censor or make cuts in (a manuscript, film, etc.). Blue Peter a blue flag with a white square raised on board a ship leaving port. blue ribbon 1 a high honour. 2 Brit. the ribbon of the Order of the Garter. blue rinse a preparation for tinting grey hair. blue roan see ROAN(1). blue rock = rock-dove (see ROCK(1)). blue stone (or vitriol) copper sulphate crystals. blue tit a common tit, Parus caeruleus, with a distinct blue crest on a black and white head. blue water open sea. blue whale a rorqual, Balaenoptera musculus, the largest known living mammal. once in a blue moon very rarely. out of the blue unexpectedly. blueness n.
[ ME f. OF bleu f. Gmc ]