The most common and most likely answer to this crossword clue is the 4 letter word HUNG
I've seen this crossword clue in Financial Times
H
U
N
G
Buddy explains!

The straight part
We know that "dropped" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dropped = hung.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HUNG mean?
HUNG verb- To be or remain suspended.
- To float, as if suspended.
- (of a ball in cricket, tennis, etc.) To rebound unexpectedly or unusually slowly, due to backward spin on the ball or imperfections of the ground.
- To hold or bear in a suspended or inclined manner or position instead of erect.
- To cause (something) to be suspended, as from a hook, hanger, hinges or the like.
- To execute (someone) by suspension from the neck.
- To be executed by suspension by one's neck from a gallows, a tree, or other raised bar, attached by a rope tied into a noose.
- (used in maledictions) To damn.
- To loiter, hang around, to spend time idly.
- To exhibit (an object) by hanging.
- To apply (wallpaper or drywall to a wall).
- To decorate (something) with hanging objects.
- To remain persistently in one's thoughts.
- To prevent from reaching a decision, especially by refusing to join in a verdict that must be unanimous.
- To stop responding to manual input devices such as keyboard and mouse.
- To cause (a program or computer) to stop responding.
- To cause (a piece) to become vulnerable to capture.
- To be vulnerable to capture.
- Of a pitcher, to throw a hittable off-speed pitch.
- Suspended by hanging.
- Having hanging additions or appendages.
- Of a jury, unable to reach a unanimous verdict in a trial.
- Of a legislature, lacking a majority political party.
- Of a computer or similar device, receiving power but not functioning as desired; working very slowly or not at all. The condition is often corrected by rebooting the computer.
- (of a person, slightly vulgar) Having a large penis (often preceded by an adverb, e.g. well hung).