The most common and most likely answer to this crossword clue is the 5 letter word FLASK
I've seen this crossword clue in The Guardian
F
L
A
S
K
Buddy explains!
The straight part
We know that "Bottle" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bottle = flask.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 FLASK mean?
FLASK noun- A narrow-necked vessel of metal or glass, used for various purposes; as of sheet metal, to carry gunpowder in; or of wrought iron, to contain quicksilver; or of glass, to heat water in, etc.
- A container used to discreetly carry a small amount of a hard alcoholic beverage; a pocket flask.
- Laboratory glassware used to hold larger volumes than test tubes, normally having a narrow mouth of a standard size which widens to a flat or spherical base.
- A container for holding a casting mold, especially for sand casting molds.
- A bed in a gun carriage.
- To invest a denture in a flask so as to produce a sectional mold.