adjective
Of a blue hue.
(informal) Depressed, melancholic, sad.
Having a bluish or purplish shade to the skin due to a lack of oxygen to the normally deep-red red blood cells; cyanotic.
(of a flame) Pale, without redness or glare.
(politics) Supportive of, run by (a member of), pertaining to, or dominated by a political party represented by the colour blue.
(astronomy) Of, dominated by, or shifted toward the higher-frequency, or "bluer", end of the electromagnetic spectrum.
(particle physics) Having a colour charge of blue.
(of steak) Extra rare; left very raw and cold.
(of a dog or cat) Having a coat of fur of a slaty gray shade.
(archaic) Severe or overly strict in morals; gloomy.
(archaic, of women) Literary; scholarly; bluestockinged.
(informal) Risqué; obscene; profane; pornographic.
(slang, dated) Drunk.
noun
(countable and uncountable) The colour of the clear sky or the deep sea; the colour midway between green and violet in the visible spectrum and one of the primary additive colours.
Anything coloured blue, especially to distinguish it from similar objects differing only in colour.
A blue dye or pigment.
(uncountable) Blue clothing.
The sky, literally or figuratively.
The ocean; deep waters.
The far distance; a remote or distant place.
A dog or cat with a slaty gray coat.
(snooker) One of the colour balls used in snooker, with a value of five points.
(entomology) Any of the butterflies of the subfamily Polyommatinae in the family Lycaenidae, most of which have blue on their wings.
A bluefish.
(Australia, colloquial) An argument or brawl.
A liquid with an intense blue colour, added to a laundry wash to prevent yellowing of white clothes.
Any of several processes to protect metal against rust.
(British) A type of firecracker.
(particle physics) One of the three colour charges for quarks.
(UK politics) A member or supporter of the Conservative Party.
A blue cheese.
(slang, uncountable) Risqué or pornographic material.
verb
(ergative) To make or become blue; to turn blue.
(transitive, metallurgy) To treat the surface of steel so that it is passivated chemically and becomes more resistant to rust.
(transitive, laundry) To brighten by treating with blue (laundry aid).
(intransitive, Australia, slang) To fight, brawl, or argue.
verb
(transitive, slang, dated) To spend (money) extravagantly; to blow.