dropper

noun

1. A utensil for dispensing a single drop of liquid at a time.

   “'Cause when the blood begins to flow When it shoots up the dropper's neck[…]”

2. One who drops something, especially one who drops a specific item to cause mischief.

   “The dropper left the suitcase with the bomb next to the garbage can.”

   “The child with the letter runs around the outside of the ring, repeating the words over and over again, and at one point drops the letter behind one of the players, who must pick it up and chase the dropper.”

3. A software component designed to install malware on a target system.
4. A fly that drops from the leaden above the bob or end fly.
5. A branch vein which drops off from, or leaves, the main lode.
6. The young bulb of a tulip, not of flowering size.
7. A dog which suddenly drops upon the ground when it sights game.
8. (Australia)A batten fixed to a post-and-wire fence to keep the wires apart.
9. (slang)A person who uses fraudulent cheques.

   “Thus an American police chief discussing the 'cheque-droppers', then peculiar to his side of the Atlantic, who were taking a toll estimated at […] Over the years, forgery has tended to be an amateur operation — a crime of opportunity.”

   “[…] 'dropper' — the person who presents the cheque at the bank or elsewhere — who takes the risk. […] On the other hand, 'kite droppers' usually work in teams.”

10. (informal)A drop shot.
11. (historical)A delivery by lob bowling (no longer legal).
12. (historical)A bowler who makes such deliveries.
13. A seat post whose height can be adjusted while riding.