(flī) v. flew or flied (def. 7), flown, fly·ing v.i.
1. To move through the air by using wings, as a bird.
2. To move through the air in an aircraft; travel by aircraft.
3. To move through the air with speed, as an arrow or bullet.
4. To wave or move in the air, as a flag.
5. To pass swiftly: The years flew by.
6. To move swiftly or with violence: The door flew open.
7. In baseball, to bat a fly.
8. To take flight; flee.
9. In hawking, to hunt with or as with a hawk.
—v.t.
10. To cause to wave or float in the air.
11. To operate (an aircraft).
12. To pass over in an aircraft: to fly the Atlantic.
13. To transport by aircraft.
14. To flee from.
15. In hawking, to hunt with a hawk.
—to fly at To attack.
—to fly in the face of To defy openly.
—to fly out In baseball, to be retired by batting a ball which is caught by an opposing player before it touches the ground.
—noun plural flies.
1. An object or device that moves or swings rapidly through the air, or has some relation to such motion.
2. A speed-regulating device, as of vanes upon a rotating shaft, used in music boxes, in the striking part of clocks.
3. Printing A long-fingered frame oscillating quickly upon a horizontal axis, taking the sheets from the tapes or cylinder of a printing press and delivering them flat upon a pile.
4. A knitting-machine latch.
5. The length of a flag measured from the staff to its farthest edge, as distinguished from the hoist.
6. That part of a flag farthest from the staff, or beyond the canton.
7. The revolving part of a vane that shows the direction of the wind.
8. Mech. a A flywheel, a weighted arm, or other mechanical device involving the flywheel principle. b The heavily weighted lever which enables a fly press to acquire momentum. c A fly press.
9. A strip or lap on a garment, to cover the buttons or other fasteners; hence, something used to cover or connect; a flap, as of a bootee.
10. An upper covering to a ridge-pole tent; also, the flap at the entrance of a tent.
11. The condition or movement of a ball when sent flying through the air as in baseball; also, the ball thus flying.
12. Waste cotton.
13. The act or state of flying; flight.
14. A public carriage; also, a delivery wagon.
15. In a theater, the space above the stage and behind the proscenium containing the borders, the mechanism for handling and setting the scenery, the overhead lights, etc.
—on the fly While flying; while in the air; in haste. [OE flēogan] Synonyms (verb): flee, flit, haste, hasten, run, soar, speed. See ESCAPE.

(flī) noun plural flies
1. One of various small dipterous insects (family Muscidae), especially the common housefly (Musca domestica).
2. Any of various other flying insects not of the family Muscidae: the Spanish fly, or the mayfly.
3. A fish hook concealed by feathers, etc., to imitate some insect.
4. plural flys A light carriage. [OE flӯge]

(flī) adjective Slang
Sharp; wide-awake.