The most common and most likely answer to this crossword clue is the 4 letter word WHEY
I've seen this crossword clue in The Guardian
W
H
E
Y
More clues leading to the result WHEY
- Dairy product put on scales, some might say
- Watery liquid from height dropping into uprooted tree
- Question imbibing English dairy product
- Question about English dairy product
- Sounds like a plan for a bit of a junket
- Tips from witch expertly creating watery liquid
- Watery stuff from two rivers being baled out of rowing boat
- Question about energy that goes into cheese-making
- For what reason put round fifth-rate nursery rhyme fare?
- What for energy must go into dairy product
Buddy explains!

The straight part
We know that "Watery stuff" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case watery stuff = whey.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 WHEY mean?
WHEY noun- The liquid remaining after milk has been curdled and strained in the process of making cheese.