The most common and most likely answer to this crossword clue is the 4 letter word EWER
I've seen this crossword clue in The Times
E
W
E
R
More clues leading to the result EWER
- Sheep runs that may hold water
- Jacob's missus maybe runs vessel
- Always apparently packing an extra five in a single square container
- In gale we rescue vessel
- Maker of beer drops brother’s pitcher
- One spouted, always inhibiting wife
- Waste carrier avoids small vessel
- Directions given to robber at first in jug
- With force away, not so many in jug
- Pitcher found in drain, missing lid
Buddy explains!

The straight part
We know that "jug" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case jug = ewer.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 EWER mean?
EWER noun- A kind of widemouthed pitcher or jug with a shape like a vase and a handle.