The most common and most likely answer to this crossword clue is the 4 letter word LAZY
I've seen this crossword clue in The Guardian
L
A
Z
Y
Buddy explains!

The straight part
We know that "Unwilling to work" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unwilling to work = lazy.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 LAZY mean?
LAZY noun- A lazy person.
- Sloth (animal).
- To laze, act in a lazy manner.
- Unwilling to do work or make an effort; disinclined to exertion.
- Causing or characterised by idleness; relaxed or leisurely.
- Showing a lack of effort or care.
- Sluggish; slow-moving.
- Lax:
- (of a cattle brand) Turned so that (the letter) is horizontal instead of vertical.
- Employing lazy evaluation; not calculating results until they are immediately required.
- Wicked; vicious.