(vulgar) Used as a further intensification of fuck in some phrases

A fly of the subfamily Psychodinae of the nematoceran family Psychodidae.

A fly, Musca autumnalis, that resembles the housefly and is a pest of cattle and horses.

A person holding a rank in the RAF, between that of pilot officer and flight lieutenant, equivalent to an Army lieutenant or Royal Navy sublieutenant.

Any of numerous species of blood-sucking flies of the family Tabanidae. / A fly of the genus Hippobosca, especially Hippobosca equina; a horse tick.

Any of the genus Asilus and allied genera of dipterous insects, of which there are numerous species; large and fierce flies which capture bees and other insects, often larger than themselves, and suck their blood.

Helaeomyia petrolei, a Californian fly whose larvae feed on dead insects that become trapped in naturally occurring petroleum pools.

(slang, archaic) To raise money on commercial notes; to obtain money as by accommodation bills, the endorser having no actual money. / Used other than figuratively or idiomatically: see fly, kite.

(archaic) aphid

Delia antiqua, a cosmopolitan pest of crops, whose larvae or maggots feed on onions, garlic and other bulbous plants.