Indigo in the form of small balls or lumps, used for blueing linen etc.

powdered azurite used as a pigment

(slang, derogatory) A police officer. / (slang) Panaeolus cyanescens, a kind of magic mushroom.

plural of blue meanie

Blue carbonate of copper; azurite.

(slang, vulgar, transitive) To leave (a person, usually a man) sexually frustrated by denying them an orgasm or abruptly ending sexual contact.

Any member of the genus Alectroenas of the pigeon family.

(mineralogy) Crocdilite

copper sulphate

Visible light towards the blue end of the spectrum generated from the screen of an electronic device.