The most common and most likely answer to this crossword clue is the 4 letter word GLEY
G
L
E
Y
Buddy explains!
The straight part
We know that "sticky clay" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sticky clay = gley.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 GLEY mean?
GLEY noun- A type of hydric soil, sticky, greenish-blue-grey in colour and low in oxygen.
- To be converted into this kind of soil.
- To squint; to look obliquely; to overlook things.