bluebottle

blue +‎ bottle

bluebottle (plural bluebottles)

1. Any of various blowflies of the genus Calliphora that have an iridescent metallic-blue body and make a loud buzzing noise whilst flying.
2. A marine jelly of the genus Physalia, which includes Physalia physalis, the Portuguese man-of-war, and Physalia utriculus, the Pacific man-of-war; a man-of-war.
3. A cornflower, a plant that grows in grain fields, Centaurea cyanus, with blue flowers resembling bottles.
4. A blue ant, Diamma bicolor, a parasitic wasp native to Australia.
5. (slang, derogatory) A police officer.

• blue-bottle fly