The most common and most likely answer to this crossword clue is the 4 letter word SNOW
I've seen this crossword clue in Independent
S
N
O
W
More clues leading to the result SNOW
- Precipitation small, at the moment
- Wintry weather in South at present time
- Precipitation beginning to settle at the present time
- Precipitation beginning to settle at present
- Wintry weather in south at present
- Precipitation ultimately unknown in Tamworth, perhaps?
- Broadcast interrupted by new interference
- . . . . succeeded immediately, producing this
- It falls slowly to begin with, at present
- Partners attending opening of observatory with cocaine
Buddy explains!

The straight part
We know that "cocaine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cocaine = snow.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 SNOW mean?
SNOW noun- The frozen, crystalline state of water that falls as precipitation.
- Any similar frozen form of a gas or liquid.
- A snowfall; a blanket of frozen, crystalline water.
- A shade of the color white.
- The moving pattern of random dots displayed on a television, etc., when no transmission signal is being received.
- Cocaine.
- To have snow fall from the sky.
- To hoodwink someone, especially by presenting confusing information.
- To bluff in draw poker by refusing to draw any cards.
- A square-rigged vessel, differing from a brig only in that she has a trysail mast close abaft the mainmast, on which a large trysail is hoisted.